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This is to certify that the
dissertation entitled

ACQUISITON OF GEMINATE CONSONANTS
IN JAPANESE BY AMERICAN ENGLISH SPEAKERS

presented by

MIKI MOTOHASHI

has been accepted towards fulfillment
of the requirements for the

Linguistics and Germanic,

 

 

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ACQUISITION OF GENflNATE CONSONANT S IN JAPANESE
BY AMERICAN ENGLISH SPEAKERS

By

Miki Motohashi

A DISSERTATION

Submitted to
Michigan State University
in partial fiilfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY
Department of Linguistics and Germanic, Asian and Afiican Languages

2007

ABSTRACT

ACQUISITION OF GENflNATE CONSONANTS IN JAPANESE
BY AMERICAN ENGLISH SPEAKERS

By

Miki Motohashi

It has been pointed out that English-speaking learners of Japanese often exhibit
timing problems in the perception and production of geminate consonants since
durational contrast is a novel phoneme for English speakers. The present study has
reported on data from the perception and production of geminate consonants in Japanese
by American learners. Based on these data, an effective way to train learners to identify
geminate consonants was developed and tested.

Four experiments were conducted. Two experiments collected perception and
production data of geminate consonants by American learners of Japanese to investigate
the way that the learners perceived and produced geminate consonants and examine
whether there were any particular phonetic contexts and identities of geminate
consonants which were particularly more difficult for learners. The conditions considered
were types of consonants; /s/, /t/ and /k/; preconsonantal segments; /sa/ and /a/,
postconsonantal segments; /u/ and /a/, and comparison between words in isolation and
carrier sentences. The results showed that the learners’ performances were affected by the
phonetic contexts and identities of geminate consonants. Specially, a combination of
fricative geminate consonant /s/ and low sonon'ty vowel /u/ was found the most difficult
to perceive, while there was no such tendency for production.

The other two experiments considered a method of training to improve perception

of such difficult geminate consonants. In addition, another issue to consider is the
modality of training. The training program was developed to investigate whether
audio-visual (AV) training would be more beneficial than auditory-only (A—only) training
to improve the learners’ perception of geminate consonants. The previous training studies
generally used auditory-modality cues; however, Hardison’s studies (e. g., 2003, 2004)
reported that L2 learners benefit from visual cues as well as auditory cues in perception
training. The present study used visual displays of waveforms of geminate consonants as
aids for learners to identify difference of mora weight between singleton and geminate
consonants. The result indicated that AV—training showed its superiority in producing
perception improvement over the A-only training. Further, the AV-training group data
showed a transfer effect of perception training to their improvement of production. This
result suggests that there is a close link between perception and production development
processes.

Further, the present study emphasizes the importance of collecting data from
learners’ performances and aims to develop an effective training program. The stimuli
used for the training were selected based on the findings from the data collected. The
effectiveness of high-variability stimulus demonstrated in the present study is compatible
with previous studies (e. g., Pisoni et al., 1999), which supported a multiple-trace memory
theory in which each event or input is encoded in memory as a trace, rather than
prototype. Through the training, all attended perceptual details were stored in memory
and modify an attention weighting scheme to perceive distinctive features in L2. It is

assumed that the bimodal training used in the present study would facilitate this process.

 

Copyright by
MIKI MOTOHASIrH
2007

ACKNOWLEDGIVIENTS

My deepest appreciation goes to my dissertation committee members. Since I Iefi
the United States three years ago to pursue my teaching career in Japan, communication
became difficult. I am grateful that the committee members always—and very
patiently—answered my questions promptly by e-mail.

I would like to thank my co-chairs, Dr. Dennis Preston and Dr. Susan Gass. Dr.
Preston always encouraged me to go on. His academic advice (as well as his sense of
humor) was always helpful. Dr. Gass always gave me helpfiil feedback and patiently read
my dissertation.

The influence of other committee members is also appreciated. I thank Dr.
Barbara Abbott for being generous with her time whenever I had questions. Dr. Mutsuko
Endo Hudson has been supportive by advising me to complete this dissertation, as well as
giving me precious opportunities to expand my teaching career. I thank Dr. Shawn
Roewen for his willingness to read my work, ask important questions, and provide
feedback and helpful suggestions.

Last but not least, I am gratefiil to Dr. Debra Hardison for her patience—and a
tremendous amount of feedback. The topic of this dissertation originated from a project
for her class. She helped me with the entire process of revising the dissertation by giving
me very specific comments on many points—not only about SLA, but also about
phonology, statistics, thesis format, etc. in a very timely manner.

I want to thank all of my friends with whom I studied at the University of

Wisconsin-Madison, and Michigan State University. I am especially gratefiil to Emiko

Magnani for her patience in reading my dissertation and giving me very helpful feedback.

I also extend many thanks to my students and colleagues at Kansai Gaidai
University in Japan for their support for collecting data. I would especially like to thank
Dr. Jeffrey Rasch for patiently proofreading my dissertation and giving me many
suggestions and comments as a linguist, which contributed to my preparation for the
defense.

I thank Hideki Saigo, as my colleague, best friend and husband, for sharing the
difficult time during the last years of completing the dissertation, giving me advice about
finishing a dissertation based on his own experience, and doing all the household chores
(especially cooking). I appreciate his patience and support. Finally, I want to thank my
parents and grandmother for always helping and encouraging me to continue my study in

the US. This work is dedicated to them.

vi

TABLE OF CONTENTS

LIST OF TABLES __________________________________________________________________________________________________________________ x
LIST OF FIGURES _______________________________________________________________________________________________________________ xi
CHAPTER 1
INTRODUCTION _________________________________________________________________________________________________________________ 1
CHAPTER 2
BACKGROUND ___________________________________________________________________________________________________________________ 7
2.1 Previous studies of geminate consonants __________________________________________________________________ 7
2.1.1 Mora in Japanese _______________________________________________________________________________________________ 7
2.1.2 Research on native speakers’ production of geminate consonants ________________ 9
2.1.3 Research on native speakers’ perception of geminate consonants _______________ 10
2.1.4 Research on nonnative speakers’ production of geminate consonants ________ 13
2.1.5 Research on nonnative speakers’ perception of geminate consonants _________ 13
2.2 Development of speech perception and production _______________________________________________ 17
2.3 Training studies ________________________________________________________________________________________________________ 2 2
2.4 Making visual information available to L2 learners ______________________________________________ 36
2.4.1 Electronic Visual Feedback (EVF) _________________________________________________________________ 36
2.4.2 Effects of instruction on production of segments and suprasegmental
features _____________________________________________________________________________________________________________ 37
2.4.3 Experimental studies of EVF __________________________________________________________________________ 40
2.5 Research questions and hypotheses ________________________________________________________________________ 42
CHAPTER 3
Experiment I ________________________________________________________________________________________________________________________ 44
3.1 Overview of the experiments _______________________________________________________________________________ 44
3.2 Objectives of Experiment I ______________________________________________________________________________________ 4 4
3.3 Method ______________________________________________________________________________________________________________________ 50
3.3.1 Participants ______________________________________________________________________________________________________ 50
3.3.2 Materials __________________________________________________________________________________________________________ 51
3.3.3 Procedure _________________________________________________________________________________________________________ 53
3.4 Results _______________________________________________________________________________________________________________________ 54
3.5 Discussion _________________________________________________________________________________________________________________ 61
CHAPTER 4
Experiment H _______________________________________________________________________________________________________________________ 69
4.1 Objectives of Experiment 11 _____________________________________________________________________________________ 69
4.2 Experimental design _________________________________________________________________________________________________ 70
4.3 Method ____________________________________________________________________________________________________________________ 70
4.3.1 Participants ______________________________________________________________________________________________________ 70
4.3.2 Materials 71

vii

4.3.2.1 Pretest and posttest __________________________________________________________________________________ 71

4.3.2.2 Instruction by electronic visual input _____________________________________________________ 71

4.3.3 Procedure _________________________________________________________________________________________________________ 72
4.4 Results _______________________________________________________________________________________________________________________ 72
4.5 Discussion ________________________________________________________________________________________________________________ 74

CHAPTER 5

Experiment HI ______________________________________________________________________________________________________________________ 76
5.1 Objectives of Experiment HI ,,,,,,,,,,, '_ _______________________________________________________________________ 76
5.2 Method ______________________________________________________________________________________________________________________ 77
5.2.1 Participants ______________________________________________________________________________________________________ 77
5.2.2 Materials __________________________________________________________________________________________________________ 78
5.2.3 Recording procedure _______________________________________________________________________________________ 79
5.2.4 Judgment of production __________________________________________________________________________________ 79

5.3 Results _______________________________________________________________________________________________________________________ 80
5.3.1 Results by phonetic conditions _______________________________________________________________________ 80
5.3.2 Error patterns ___________________________________________________________________________________________________ 85
5.4 Discussion _________________________________________________________________________________________________________________ 86

CHAPTER 6

Experiment IV ______________________________________________________________________________________________________________________ 90
6.1 Objectives of Experiment IV ___________________________________________________________________________________ 90
6.2 Method ______________________________________________________________________________________________________________________ 92
6.2.1 Participants ______________________________________________________________________________________________________ 92
6.2.2 Pretest _______________________________________________________________________________________________________________ 92
6.2.2.1 Production test _________________________________________________________________________________________ 92
6.2.2.2 Perception test _________________________________________________________________________________________ 92
6.2.2.2.] Materials _________________________________________________________________________________________ 93

6.2.2.2.2 Procedure ________________________________________________________________________________________ 94

6.2.3 Perception Training _________________________________________________________________________________________ 94
6.2.3.1 Training materials ___________________________________________________________________________________ 94
6.2.3.2 Training procedure __________________________________________________________________________________ 98

6.2.4 Posttest ____________________________________________________________________________________________________________ 100
6.2.4.1 Perception test and production test ______________________________________________________ 100
6.2.4.2 Generalization test ________________________________________________________________________________ 100
6.2.4.3 Follow-up interview ______________________________________________________________________________ 101.

6.3 Results _____________________________________________________________________________________________________________________ 101
6.3.1 Comparison of training types ________________________________________________________________________ 102
6.3.2 Results of generalization test ________________________________________________________________________ 103
6.3.3 Results of the AV-group _________________________________________________________________________________ 104
6.3.3.1 Word level vs. sentence level _______________________________________________________________ 104
6.3.3.2 Word-level perception ___________________________________________________________________________ 106
6.3.3.3 Sentence-level perception _____________________________________________________________________ 108

6.3.4 Error pattern (AV group) ________________________________________________________________________________ 111
6.3.5 Production test ________________________________________________________________________________________________ 112
6.3.5.1 Judgment of production ________________________________________________________________________ 113

viii

6.3.5.2 Results
6.3.6 Individual development for the AV training group ______________________________________
6.3.7 Follow-up interview responses ______________________________________________________________________
6.4 Discussion

CHAPTER 7

....................................................................................................

CONCLUSIONS
7.1 Summary of findings ______________________________________________________________________________________________
7.2 General discussion

--------------------------------------------------------------------------------------------------

7.3 Limitations of the study and fiirther study suggestions .......................................

APPENDICES

APPENDIX A: Perception test _____________________________________________________________________________________
APPENDIX B: Production test

REFERENCES

...................................................................................................................

ix

113
116
119
121

124
124
125
135

140
140
146

150

LIST OF TABLES

Table 2.1 Japanese special morae “tokushu-haku” ________________________________________________________________ 7
Table 2.2 Stop closure and frication duration of single/geminate consonant pairs ___________ 16
Table 3.1 Examples of test items by phonetic structures ____________________________________________________ 53
Table 5.1 Examples of the test items ____________________________________________________________________________________ 79
Table 6.1 Examples of the test items ____________________________________________________________________________________ 94
Table 6.2 Examples of the geminate consonants _______________________________________________________________ 101

Table 6.3 Mean percentage of perception accuracy in pretest and posttest and increase
rate of AV—group _________________________________________________________________________________________________ 117

Table 6.4 Mean percentage of production accuracy in pretest and posttest and increase
rate of AV-group _________________________________________________________________________________________________ 118

LIST OF FIGURES

Figure 2.1 Duration of words in Japanese and English _______________________________________________________ 10
Figure 3.1 Sonority hierarchy _______________________________________________________________________________________________ 46
Figure 3.2 Sonority index ______________________________________________________________________________________________________ 46
Figure 3.3 CVC word ____________________________________________________________________________________________________________ 43
Figure 3.4 CVCCV word _____________________________________________________________________________________________________ 48
Figure 3.5 Mean percent correct identification by level of proficiency _____________________________ 55
Figure 3.6 Mean percent correct identification by item condition _____________________________________ 56

Figure 3.7 Mean percent correct identification at sentence-level by item condition 58

Figure 3.8 201 students’ perception of /CC+u/ at word-level _____________________________________________ 59
Figure 3.9 201 students’ perception of /CC+u/ at sentence-level _______________________________________ 60
Figure 3.10 Waveform of lakku/ ___________________________________________________________________________________________ 63
Figure 3.11 Waveform of /assu/ ____________________________________________________________________________________________ 64

Figure 3.12 (a) The syllabification pattern of a geminate consonant when it is perceived
correctly; (b) The patter when a geminate is misperceived as a singleton _____ 66

Figure 3.13 Syllabification pattern of a geminate consonant when the word is
misperceived as containing a long vowel ________________________________________________________ 67

Figure 4.1 Mean percent correct identification of /ss/ geminate consonants _____________________ 73

Figure 5.1 Comparison of judges’ mean scores between word level and sentence level for

single and geminate production ________________________________________________________________________ 81
Figure 5.2 Mean production scores by consonants _____________________________________________________________ 82
Figure 5.3 Mean production scores by vowels following geminate consonants _______________ 83
Figure 5.4 Mean production scores by preceding segment types _______________________________________ 84
Figure 5.5 Ratio of errors: production of geminate consonants /CC+u/ ____________________________ 86

xi

Figure 6.1 Waveform display ________________________________________________________________________________________________ 96
Figure 6.2 Exercise questions display __________________________________________________________________________________ 97
Figure 6.3 Feedback display _________________________________________________________________________________________________ 98
Figure 6.4 Mean percent correct identification for perception pretest and posttest ________ 103
Figure 6.5 Mean percent correct identification for posttest and generalization test _______ 104

Figure 6.6 Mean percent correct identification pretest and posttest for word-level and
sentence level geminate consonants _______________________________________________________________ 105

Figure 6.7 Mean Percent correct identification for each consonant (/s/, /t/, /k/) and each
post-consonantal vowel (/a/, /u/) in pretest and posttest for word—level
geminate consonants ________________________________________________________________________________________ 107

Figure 6.8 Mean Percent correct identification for each consonant (/s/, /t/, /k/) and each
post-consonantal vowel (/a/, /u/) in pretest and posttest for sentence-level

geminate consonants ________________________________________________________________________________________ 109

Figure 6.9 Mean percent misperception of geminate consonants as long vowels for each
consonant type in pretest and posttest ____________________________________________________________ 112

Figure 6.10 Mean ratings for the production test ______________________________________________________________ 114

Figure 6.11 Mean production rating for each consonant type in pretest and posttest for the
AV training group ____________________________________________________________________________________________ 115

xii

CHAPTER 1

INTRODUCTION

The present study will address issues in the acquisition of second language (L2)
phonology by English speakers, focusing on geminate consonants in Japanese.
Specifically, the main experiment that provides data for the present study was conducted
to investigate whether adult learners of Japanese could be trained to perceive and produce
geminate consonants accurately. In order to determine effective training materials and
methods, the present study also examined what kinds of geminate consonants were most
difficult for learners to perceive and produce. The rationale for choosing geminate
consonants is the notorious difficulty which many learners of Japanese as a second
language have with durational contrasts. Japanese is a mora-timed language, and duration
is contrastive, while such contrasts do not exist in English. It has been reported that
learners whose first language (L1) is English often have problems with the perception
and production of geminate consonants, as well as with other timing morae in Japanese
(Toda, 2003). These problems often lead to miscommunication.

In the present study, participants were given perception training in order to
examine the possibility of improvement due to such training in their L2 performance. A
number of studies have reported that intensive laboratory training resulted in
improvement in learners’ performance (e. g., Jamison & Morosan, 1986, 1989; Logan,
Lively & Pisoni, 1991; Pisoni, Aslin, Perey & Hennesy, 1982; Yamada, Akahane-Yamada
& Strange, 1995, Hardison, 2003, 2004). Further, it has also been reported that the effects

of training in perception were transferred to ability in production (e. g., Hardison, 2003;

Bradlow, Pisoni, Akahane-Yamada & Tohkura, 1997; Catford & Pisoni, 1970; Rochet,
1995). Through investigation of the effect of perception training in modifying foreign
accented production, we will also examine issues of the relationship between perception
and production.

The present study also emphasizes the importance of collecting data from
learners’ performances and aims to develop an effective training program to train
English-speaking learners’ perception as well as production of geminate consonants in
Japanese. Many of the previous studies of geminate consonants in Japanese limited their
focus to stop consonants, and few studies have referred to the types of phonetic contexts
in which geminates occur. Therefore, it is necessary to examine whether there are any
particular phonetic contexts that make perception and production of a geminate
consonant more difficult for learners. Based on the outcome of such research, we could
find ways to focus training more specifically and to develop effective materials for
training.

Although previous training studies have been shown to be effective, the
methodologies have not been evaluated thoroughly enough. For example, traditionally the
dominant method for examining learners’ development of the ability to perceive new,
diflicult nonnative contrasts was laboratory auditory training, by using a two-alternative
identification or discrimination tasks involving minimal pairs in isolation (e.g.,
Akahane—Yamada, Tohkura, Bradlow & Pisoni 1996; Ingram & Park, 1998; Ziolkoski,
Usami, Landahl & Tunnok, 1992), but few studies provide details of why the particular
methods themselves were adopted. The present study aims to suggest a more effective

training method by actually collecting and examining in detail the perception and

production data of learners, determining in greater detail where errors occur.

Another issue to consider is the modality of training. The above mentioned
previous training studies generally used auditory-modality cues; however, Hardison’s
studies (e. g., 2003, 2004) reported that L2 learners benefit from visual cues as well as
auditory cues in perception training, and further showed that bimodal training was
especially effective on the more phonologically difficult segments from the point of view
of the learners’ L1. The psychological evidence supports the claim that information from
one modality helps to reinforce another’s sensory pathway, and the combination of
information from different modalities enhances the development of the learning process
(do Sa & Ballard, 1997). The present study examined the effect of combining visual cues
with auditory cues to train the learners to identify geminate consonants, and the results
were compared with auditory-only training.

Hardison (2005a) used visual displays of pitch contours of French as visual cues
to train English speakers and reported their effectiveness as visual input. The present
study used visual displays of waveforms of geminate consonants as aids for learners to
identify difference of mora weight between singleton and geminate consonants. A
growing number of language teaching programs have been utilizing computer-assisted
instruction for perception and pronunciation teaching to enhance self-monitoring skills by
learners. Recent developments in technology allow researchers to display formant
frequency graphs, waveforms, or spectrograms on computers to teach both
suprasegmental (stress, rhythm and intonation) and segmental features (e.g.,
Anderson-Hsieh, 1994, 1996; Chun, 1989, 1998; de Bot, 1983; Hardison, 2004, 2005;

Levis & Pickering, 2004; Molholt, 1988; Weltens & de Bot, 1984). Such visual displays

have been used mainly as production training to give learners feedback on their own
production. As a potential alternative training method, the present study proposes
computer-assisted perception training. Visual information which consists of graphs of the
waveforms of geminate consonants is expected to facilitate learners’ sensitivity to mora
timing in Japanese and improve their perception and, subsequently, production as well.
As shown in several studies mentioned above, the effect of perception training can be
carried over to production ability without additional explicit production training. The
present study aims, therefore, to examine whether this transfer effect can be observed in
the acquisition of geminate consonants. The training method of the present study was
developed on the analysis of actual data which were able to pinpoint the difficulties that
learners of Japanese a second language have.

There are also other advantages of computer-based instruction. For example, it
appears that computer-delivered materials are helpful in reducing the nervousness that
students may feel in the classroom, and easy access may encourage learners to use a
computer program on a daily basis. The present study suggests that pronunciation training
should be incorporated into everyday classroom teaching, in addition to intensive
laboratory training, which has also been shown to be highly effective in previous studies.

In sum, the present study was motivated by the following research questions:

1) How do the learners perceive and produce geminate consonants? Is there any
particular phonetic context of geminate consonants, which makes perception and/or
production more difficult for learners?

2) Are audio-visual instruction and training using visual displays of waveforms of

geminate consonants more beneficial than auditory-only information?

3) Does perceptual training improve production ability without any additional explicit
production training?

To examine the first research question, Experiments I and III described below
were conducted to collect data on the perception and production, respectively, of
geminate consonants by American English speakers. As reviewed in the following section,
previous studies have shown that learners perceive and produce geminate consonants in
different ways from native speakers of Japanese. However, the results of these studies
vary according to many factors including the data collection methods and the focus of the
analysis. The present study focused on the phonetic form and context of geminate
consonants, that is, the types of consonants and the preceding and following segments;
few previous studies have examined these factors. Research questions 2 and 3 are tested
by Experiments II and IV. Experiment II was conducted to test the efi’ect of electronic
visual input on the perception of geminate consonants, and Experiment IV was a pretest
and posttest of the experimental training study using visual input in perception training,
to examine whether the training is effective and whether the effects of such training
transfer to improvement in production.

The organization of the remainder of this dissertation is as follows. Chapter 2
reviews the relevant literature to explore the above research questions, mainly regarding
1) perception and production of geminate consonants by native and nonnative speakers of
Japanese; 2) the relation between perception and production and the effects of training to
improve ability in these two domains; and 3) the effects of electronic visual feedback on
acquisition of L2 phonology. Chapters 3 through 6 discuss the methodology and results

for Experiments I through IV, respectively. Chapter 7 provides a general discussion of the

results of the experiments and the pedagogical implications.

CHAPTER 2

BACKGROUND

2.1 Previous studies of geminate consonants
2.1.1 Mora in Japanese

The duration of vowels and consonants is a contrastive feature in Japanese while
it is not in English. A mora is a unit of timing, and each mora is supposed to take about
the same length of time to pronounce (Ladefoged, 1993). As the number of morae
increases, the total duration of the syllable increases proportionately. Syllable duration,
and thus total word length is attributable to the number of morae. There are three kinds of
special morae in Japanese; geminate consonants, moraic nasals, and those resulting from
long vowels, and they are called ‘tokushu-haku’ (special timing morae). To perceive and
produce these special morae, sensitivity to timing is necessary, and it is a difficult task for
learners of Japanese whose native language does not have durational contrasts to acquire
native-like perception and production. Below are examples of minimal pairs of both

tokushu-haku and non-tokushu-haku:

Table 2.1

Japanese special morae “tokushu-haku ”

 

 

Long vowel Geminate consonants Moraic nasal

/kiite/ “Listen.” /kitte “stamps” /kiNka/ “gold coins”

(3 morae; 2 syllables) (3 morae; 2 syllables) (3 morae; 2 syllables)
lkite/ “Come.” lkite/ /kika/ “vaporization”
(2 morae; 2 syllables) (2 morae; 2 sfllables) (2 morae; 2 syllables)

 

Although basic Japanese syllables are open, consisting of /CV/, syllables with
geminate consonants and moraic nasals are exceptionally closed ones. According to
Shibatani (1990), geminate consonants consist of a non-nasal consonant coda followed by
a homorganic consonant onset in the following syllable. This homorganic geminate
consonant adds one mora. For example, a word containing a geminate consonant like
kitte “stamps” is considered a three—mora word, while its single consonant counterpart is
counted as a two-mora word, e. g., kite “come,” and again this difference in duration is
contrastive as shown in Table 2.1.

By actually measuring the duration of words produced by native speakers,
research has shown that each mora has equal duration (e. g., Port, Dalby & O’Dell, 1987;
Sugito, 1999). For example, Port et a1. (1987) measured the duration of a number of
words which contain different numbers of morae, including words with geminate stops
and long vowels, and found that the duration of words with an increasing number of
morae increased by nearly consistent increments. It would appear that native Japanese
speakers discriminate between short and long vowels, as well as single and geminate
consonants, by the relative duration of the target vowel or consonant.

With morae of relatively equal length, Japanese therefore has isochronous timing
of morae, while English has syllables and/or morae of difl‘erent lengths, most notably as a
result of stress; i.e., stressed syllables are longer. Duration of units, however, is not
systematically contrastive in English. It has been pointed out that English-speaking
learners of Japanese often show timing problems in the production and perception of long
vowels and geminate consonants, since durational contrast is novel for them. Thus, not

only learners, but also instructors need a clear understanding of how native Japanese

speakers make durational contrasts.

2.1.2 Research on native speakers’ production of geminate consonants

A number of studies have conducted acoustic analyses to see how native
speakers of Japanese actually produce a geminate as opposed to a single consonant. It has
been found that one of the most important acoustic cues for producing the distinct
duration of a geminate stop consonant is the closure duration of the first part of the
geminate. The results of these previous acoustic studies are mostly consistent; the total
duration of a syllable with a geminate consonant is approximately 50% longer than that
of its single consonant counterpart, though there is a discrepancy in actual measurements
as to whether the single/geminate duration ratio is exactly 2:3 or not.

Homma (1981) measured word duration of two and three mora words with
geminate stops (/pp/, /tt/, and /kk/) and their singleton consonant counterparts produced
by native Japanese speakers. She found that the ratio duration between words with single
stops and those with geminated stops was about 2:3, confirming that the morae of
geminates are isochronous timing units. Such duration was not affected by the
phonological context of types of preceding and following consonants and vowels.

Sugito (1999) measured the duration of one- to five-mora words with geminate
stops and found that words with an increasing number of morae increase in duration by
nearly constant increments. She also conducted the same experiment with English native
speakers, having them read English words, and pointed out that English syllables are,

unlike morae in Japanese, inconsistent in their duration, as shown in Figure 2.1.

 

 

 

Duration of words in Japanese spoken by Y. T.

 

 

 

 

 

 

 

 

 

 

 

 

0.8
0.7
0.8

.0
(a

Word duration in sec.
9 o
N -§

.0
‘

 

1 2 3 4 5
# of syllables in a word

0.6
d 0.5 /’
0
(I) /
.E 0.4
c /
.9
E 0.3 /
3
P 0.2
a
L
o /
3 0.1 v

0 4 I I
1 2 3 4
# of morae in a word
. . . j
Duration of words in English spoken by R. E.
0.9

 

 

I

Figure 2.1. Duration of words in Japanese and English (Sugito (1999); reproduced from

p.69)

2.1.3 Research on native speakers’ perception of geminate consonants

Researchers have also been intrigued by the question of what acoustic cues

native Japanese speakers use to discriminate durational contrasts. It is generally agreed

10

that native Japanese speakers use closure duration of the first part of a geminate
consonant as a primary cue in discriminating between two- and three-mora words.

For example, Min (1987, 1993) used digitally edited stimuli made from
two-mora words and their three-mora geminated counterparts. Using a stimulus such as
/ita/, the stop closure duration between /i/ and /ta/ was gradually lengthened in 10 ms
steps from 110 ms to 250 ms (15 different lengths altogether). The participants were then
asked to tell whether they heard lita/ or /itta/. The results showed an apparent perceptual
categorical boundary at 160-180 ms among native speakers. Fujisaki and Sugito (1977)
also used synthesized stimuli manipulating the closure duration of the first part of a stop
geminate consonant and had native Japanese speakers discriminate between their
perceptions of geminate and single consonants. They reported that the closure duration
played the most important part in discrimination, and the perceptive boundaries for the
native Japanese speakers to distinguish a single from a geminate consonant were
categorical. Many other studies indicate similar findings (e. g., Fukui, 1978; Hirato &
Watanabe; 1987; Toda, 1998).

Besides closure duration, there have been some studies which show that pitch
accent also influences native speakers’ perception of durational contrasts. Ofuka (2003)
also used synthesized stimuli to examine the relationship between pitch accent location
and the perception of durational contrasts. Pitch accent is contrastive in Japanese, e. g.,
minimally contrastive /ame/ (H(igh)-(L(ow)) and /ame/ (LH) are different words which
mean “rain” and “candy,” respectively. She examined the perceptual boundary between a
singleton consonant word /kata/ “shoulder” (HL) and its geminated counterpart lkatta/

“won” (HLL) and another pair /kata/ “form” (LH) and /katta/ “bought” (LHH), by

11

manipulating the closure duration of stimuli by 10 ms in ten steps between /kata/ and
/katta/ in both pitch accent patterns. She found that native Japanese speakers were
affected by the location of pitch change so that there is a significant difference between
the two pitch accent patterns in the placement of the perceptual boundary; the LHH
pattern in /katta/ “bought” required a longer closure duration than the HLL “won” pattern
to be perceived as containing a geminate.

Furthermore, Hirata (1990a) distinguished word-level from sentence-level
perception. In her experiment, native speakers seemed to use different acoustic cues at
different levels. In word-level perception, preceding vowel length as well as stop closure
duration were utilized by native speakers as acoustic cues to discriminate single and
geminate consonants. She concluded that the ratio of the closure duration of the
consonant to the duration of the preceding vowel was a crucial acoustic cue. Ifthis ratio
is short, the consonant is perceived as single, but if it is long it is perceived as a geminate.
In the sentence-level perception, the distinction is made based on the speed of the units
following geminate consonants. A single consonant can be perceived as a geminate
consonant if the following parts of an utterance are read fast, and geminates can be heard
as single consonants if the following parts of an utterance are read slowly.

In sum, for native speakers, the acoustic cues for durational discrimination are
not limited to a single factor; the cues may include the duration of the preceding vowel,
the closure duration of the stop, and the speed of the following elements, depending on
whether perception occurs at word level or sentence level. Despite such interacting

conditions, however, native speakers have clear and consistent perception of durational

contrasts.

12

2.1.4 Research on nonnative speakers’ production of geminate consonants

It has been reported by many researchers that the timing control of geminate and
single stop closures differs significantly between native speakers (NS) and nonnative
speakers (NN S), which contributes to the characterization of an accent as “foreign.”
Han (1992) reported that her American subjects’ closure duration of stop geminate
consonants was consistently shorter than that of the NS subjects. On the other hand, Toda
(1994) claimed that it was not only the shorter duration of geminate consonants and long
vowels, but also the longer duration of single consonants and short vowels, which made
learners sound like they were producing geminate consonants and long vowels. As a
result, her Australian subjects tried to produce geminate consonants which were even
longer than their already lengthened single counterparts, and this adjustment resulted in a

noticeable foreign accent.

2.1.5 Research on nonnative speakers’ perception of geminate consonants

As discussed so far, previous studies have generally agreed that the absolute
closure duration of a stop consonant is one primary cue for native speakers of Japanese
for discriminating between durations of consonants. Researchers are also interested in
seeing whether learners of Japanese use the same acoustic cue.

Most of the previous studies of the perception of geminate consonants by
nonnative speakers have been carried out to determine the categorical boundaries of
perception of contrasts using synthetic stimuli. Inaccurate perceptual boundaries of
closure duration for the single vs. geminate discrimination will cause faulty perception by

nonnative speakers. The results agreed that nonnative speakers would perceive the stimuli

13

as geminate consonants when they had shorter closure duration than was required by
native speakers, but in general, such a perceptual boundary was not categorical, but rather
blurred and continuous (e. g., Hirata, 1990b; Min, 1987; Nishibata, 1993). In Min (1987),
Korean speakers’ results were compared with those of native participants. The results
showed an apparently categorical boundary among native speakers, while nonnatives did
not have such a clear boundary. Min further found that, while native speakers used
closure duration as an acoustic cue for perception, some Korean learners, though too
small a number to generalize from, tended to depend on additional phonetic
characteristics such as tenseness and aspiration of the consonant as acoustic cues.

Korean and Chinese speakers in Minagawa and Kiritani’s (1996) study, and Thai
speakers in Minagawa’s (1996) study, were found to be affected by pitch accent types
when discriminating single and geminate consonants. In a High-Low (HL) accent context,
the error pattern of C-)CC (mishearing a single as a geminate consonant) was
significantly higher than that of CC-9C (mishearing a geminate as a single consonant),
but in the Low-High (LH) accent context there was no difference in error types. Since the
acoustic measurement of the stimuli revealed durational differences of postconsonantal
vowel duration between the HL and LH contexts, that is, the average postconsonantal
vowel duration in an HL accent context is shorter than in an LH accent context, closure
duration to postconsonantal duration ratio was suggested as a possible acoustic cue for
Korean and Chinese speakers in judging the single vs. geminate contrast. In contrast,
according to Hirato and Watanabe (1987), the perception of the single vs. geminate stop
contrast by native Japanese speakers is not affected by postconsonantal vowel length. In

addition, Toda (1998, 2003) reported that, while NS were affected by preconsonantal

14

vowel duration, NNS did not show such an influence.

Another interesting finding is in Yamagata and Preston’s (1999) study. Their
study showed that the learners (L1 was English) often perceived long vowels in Japanese
loanwords, which native Japanese speakers spelled with geminates instead. Although the
learners failed to geminate, they were successful in giving the target words the correct
number of morae.

Enomoto (1989) and Toda (2003) firrther reported a learning effect through
formal instruction, in which advanced level learners came to acquire a clearer perceptual
boundary for geminate consonants, compared to the beginning learners.

In summary, there may be different acoustic cues which learners of Japanese
might depend on. Although the findings on perceptual cues used by native speakers are
consistent among researchers, there has been little agreement and no clear generalization
on what acoustic cues nonnative speakers use to distinguish geminate/single consonants.
This is because each research program is different, for example, in the subject’s L1, the
phonetic contexts of the stimuli, the data collection method, or the levels of proficiency
of the subjects.

The amount of research which focuses on the correlation between learners’
perceptual ability and the types of phonetic contexts of the stimuli is specially limited.
Most studies have examined stop consonants (e. g., Minagawa, 1996; Nishibata, 1993),
except Toda (1998) and Hayes (2002) which also included fricatives (/ss/).

Hayes (2002) conducted an experiment to examine the relative perceptibility of
the contrasts based on durational differences among particular types of single/geminate

contrasts. To analyze the duration of single/geminate consonants acoustically, a fricative

15

/s/ and two stops /t/ and /k/ were chosen for test items. She hypothesized that differences
in durational contrasts between single and geminate consonants belonging to different
natural phonological classes would affect the learners’ perception of the
singleton-geminate contrast.

The subjects of the study were to listen to minimal pairs, 60 of the same word
and 60 with different words, and then to tell whether the pair that they had just heard was
the “same” or “different.” As seen in Table 2.3, since the difference in duration between
a single /t/ and a geminate /tt/ is larger than the difference between both the /s/ and /ss/
pair and the /k/ and /kk/ pair, she hypothesized that the discrimination of /t/ and /tt/
should be the easiest. On the other hand, there should be no difference in difficulty

between /s/ contrasts and /k/ contrasts, since they have little durational difference.

Table 2.2

Stop closure and frication duration of single/geminate consonant pairs (Hayes, 2002,

p.32)

 

 

t/tt k/kk s/ss
Single duration 95.7 81.7 136.1
Geminate duration 276.1 223.6 270.1
Difference (geminate duration 180.3 141.9 134.0
minus single duration) (in msec)

 

Her hypothesis was supported by the results of the experiment. However,
learners do not usually encounter such situations, in which they can compare single and

geminate counterparts for discrimination. Therefore, it is hard to say that this result

16

reflects the reality of learners’ perception in other context.

Further, the geminate consonants used as stimuli in previous studies differed in
phonetic contexts, i.e., they were of various consonant types and had various preceding
and following elements. One of the objectives of this present study is to examine more
comprehensively how learners perceive and produce geminate consonants and whether
their perception as well as production is affected by such phonetic conditions. In addition,
we have seen that nonnative speakers’ perception and production of geminate consonants
are different from native speakers’; however, there have been few studies of how these
two abilities are related, except Akahane-Yamada (1999), whose study was limited to
stops. It is important to explore this issue further in order to clarify the details of the
fundamental problems which learners might have in acquiring geminate consonants. The
next section will review general views on the development process of perception and

production by adult L2 learners.

2.2 Development of speech perception and production

The view that perceptual development comes before production development is
consistent with the results of a number of experiments which have been concerned with
the relationship between L2 perception and production in the course of L2 acquisition.
Many such studies suggest that perception plays an important role in production, and
production problems result not only from motoric difficulties but also from perception
problems.

Flege, Munro, and MacKay (1995) suggested that production inaccuracy of the

Italian learners in their study might have been due to a perceptual problem; they argued

17

that an L2 phone must be perceived in a firlly native-like fashion if it to be produced in a
fully native-like fashion. Thus, they argue, perception should come before production;
although correct perception does not guarantee correction production, it is a prerequisite
for it. Rochet (1995) also observed the role of perception in foreign-accented
pronunciations of L2 sounds. His study examined perception and production of the
French high front rounded vowel [y] by untrained Portuguese and English speakers,
whose native languages contain only two high vowels (/i/ and /u/). In the perception test
to identify vowels along a synthetic high vowel continuum, native French speakers
identified a stimulus with the F2 values between 1300 and 1900 Hz as /y/, but Portuguese
speakers identified it as /i/ and English speakers as /u/. Based on this result, Rochet
hypothesized that an imitation task would indicate a similar tendency; when /y/ was
produced incorrectly, Portuguese speakers tended to produce it more /i/-like, whereas
English learners produced more /u/-like vowels. The results supported his hypothesis;
therefore, he claims that foreign-accented pronunciation by untrained speakers may be
perceptually motivated. This perception precedence idea can be also observed in several
other studies (e. g., Aslin, Pisoni, Hennesy & Perey, 1981; Barry, 1989; Bohn & F lege,
1990)

However, there have been reports which showed opposite tendencies. Sheldon
and Strange (1982), replicating Goto (1971), collected data from Japanese learners of
English regarding the English liquids /r/ and /l/, which are not contrasted in Japanese. The
data showed that the subjects performed better and more accurately on the production of
/r/-/l/ contrasts than in perception. The data included perception test materials involving

minimal pairs with /r/ and /l/ and the subjects’ judgments regarding their own productions

18

of the pairs. According to Sheldon and Strange, “perceptual mastery of a foreign contrast
does not necessarily precede adult learners’ ability to produce acceptable tokens of the
contrasting phonemes” and “may lag behind production mastery” (p. 254). Flege and
Efling’s (1987) experiment with Dutch speakers of English showed that their subjects
were able to produce a substantial voice onset time (VOT) difference between the /t/
phonemes in Dutch and English, but they did not show such good discrimination in
perception. Further, Mack (1989) also conducted studies which showed that production
can be more accurate than perception. Gass (1984) examined the perception of L2
learners of English of the VOT of /b/ and /p/ in initial positions by using a forced-choice
task with synthesized stimuli, and the learners’ production data were also collected.
Perception data showed an unclear, continuous distinction between the segments,
compared with the native speakers’ clear categorical boundaries. As opposed to this
nonnative-like perception, the learners could produce /b/ and /p/ in native-like fashion.
Thus, in this study, nonnative speaker production was in advance of perception.

However, as Flege (1991) and Mack (1989) pointed out, these results have to be
interpreted carefirlly. For example, the data from the Japanese learners of English in
Sheldon and Strange’s (1982) study may have been influenced by the formal English
training in production which Japanese school students had received, i.e., instruction to
use articulatory strategies such as “to say /l/, combine the features of the Japanese X and
Y sounds” (F lege, 1991, p. 265). Thus, the types of input which the subjects have been
given should also be considered cautiously to determine precisely how the data collected
could point to a specific process of L2 development.

One of the findings in Sheldon (1985), which reanalyzed the Korean learners’

19

data in the US. reported by Borden, Gerber and Milsark (1983), was that the precedence
of production by perception decreased as the Korean learners’ time residing in the U. S.
increased. This could be interpreted as an effect of instruction as Sheldon and Strange
(1982) argued above. Sheldon hypothesized that a functional perceptual level in an L2
learner might be enough for communication purposes, while heavily accented
productions are socially less accepted, with the consequence that L2 speakers would feel
more pressure to improve production than perception. Bohn and Flege (1990) also agreed
that speech production was more subject to social control than perception, and as a result,
the perception of a new contrast showed more resistance to L2 experience than the
production of the contrast did.

Although no conclusive determination has been made, we can assume that
speech perception and production capacities of individuals have great overlap. It is
important to consider both of the areas simultaneously. To explain the relation between
L1 and L2 in perception and production, and predict difficulties that learners tend to have,
F lege (1995) and Best (1995) proposed the following L2 developmental models.

Best (1995) proposed the “Perceptual Assimilation Model (PAM),” which
hypothesizes that L2 speakers perceive nonnative sounds based on similarities to or
discrepancies with the L1 phones which are closest to them in terms of the manner of
articulation. The model predicts an L2 discrimination ability that depends on the degree
to which an L2 contrast can be associated with L] categories. Thus, for L2 learners,
certain contrasts in L2 are easier to discriminate than others, while some are more
diflicult. For example, /r/ and /1/ present the most difficult contrast for Japanese learners

of English to master since these two phones are identified as the same Japanese phoneme,

20

a situation which is called ‘single category contrast.’

Similarly, Flege (1995) developed the ‘Speech Learning Model (SLM),’ which
hypothesizes that L2 sounds that are perceptually similar to sounds in L1 are more
difficult to acquire accurately than sounds that are dissimilar to any sounds in L1, and L2
speakers try to assimilate a new L2 phone to a close Ll phone although the two phones
are acoustically different. This indicates that such L2 learners have not detected the
phonetic differences between an L2 sound and the most similar L1 sound, which results
in foreign accents. The greater the phonetic distance between an L1 phone and the closest
L2 phone is, the more easily the L2 learner can detect the difference. Greater phonetic
distance facilitates the eventual establishment of a phonetic category.

Both models assume that perceptual learning occurs first but the perception and
production skills develop in parallel, although this prediction that perception
development is followed by production is not always true. However, as we have seen,
production depends on perception in certain ways, although its development may not
always follow perception development. We can therefore assume that production
difficulties may be associated with perception difficulties. As the SLM and PAM suggest,
since learners are language-specific perceivers of speech sounds and tend to adjust their
perception to the phonetic characteristics of speech segments found in their L1 5,
nonnative-like perception often occurs during the course of L2 acquisition. The previous
linguistic experience with L1 might influence the way L2 sounds are perceived, at least in
the early stages of L2 perceptual category development.

Jusczyk (1993, 2000) proposed a model of the development process of infant

speech perception, which can be applicable to the L2 acquisition process, too. Infants

21

have an innate auditory analyzer which can process any potential L1 at the initial stage of
processing of speech signals. A set of auditory analyzers provide a preliminary
description of the spectral and temporal features present in the acoustic signal. Once
language is acquired, the output of the auditory analyzers is weighted to give prominence
to those features that are the most critical to distinctive phonological features. This
“weighting scheme” is a way of directing attention to features critical for recognizing and
distinguishing words in a particular native language. For example, information from
auditory analyzers concerning aspiration in syllable-initial voiceless and voiced stops
would receive heavy weighting in the acquisition of English, but not of French. Therefore,
to acquire a new language, a listener must learn a new weighting scheme in order to be
attuned to the target language. Many studies of first language acquisition reported that
children’s linguistic ability to learn to discriminate between new contrastive features
decreases after a certain age. This is not a loss in auditory capability, but rather a
reorganization of the perceptual space optimal for L1 (Guion & Pederson, 2002). Since
L2 learners tend to fall back on the weighting scheme used for the native language, a new
weighting scheme must be developed. They must learn to alter the focus of attention,
which affects the way in which speech sounds are perceived (Jusczyk 1993).

Based on the idea that perceptual space is modified by experience (Nosofsky,
1986), a number of training studies have been conducted in order to examine how adult

learners can alter such focus of attention; they are reviewed in the following section.

2.3 'fiaining studies

Earlier researchers have postulated that the poor performance observed in adult

22

learners’ perception and production was due to a permanent change in the perceptual or
sensory mechanisms as a result of selective early experience (Pisoni, Aslin, Perey &
Hennesy, 1982). On the other hand, training experiments have been conducted based on
the assumption that it is possible to train adult learners to perceive and/or produce novel
L2 phonemes. This implies that adult learners’ perceptual and/or productive systems can
be modified. Such training studies generally aim to 1) find the cause of difficulty in
acquiring new L2 phones; 2) discover how capabilities of the adult perceptual system are
modified; 3) show that linguistic experience has a substantial efl’ect on speech perception;
4) find an effective way for L2 learners to acquire difficult sounds; and/or 5) examine
firrther the relationship between perception and production.

In the early studies which showed the effectiveness of training, researchers were
interested in the perception of voicing contrasts in stops. Pisoni et al. (1982) trained
monolingual English speakers to identify and discriminate VOT contrasts that are not
phonemically distinctive in their native language. For the experiment, synthetic VOT
stimuli based on measurements of natural speech were used to train the subjects to
identify -70, 0, and 70 ms VOT synthetic stimuli (voiced, voiceless unaspirated and
voiceless aspirated stops, respectively). Whereas English has only a two-way contrast of
voiced and voiceless, and the features aspirated and unaspirated are not contrastive, the
results showed that adult learners could perceive an additional perceptual contrast easily
in the laboratory after a short training period (1 hour a day for 4 days). Thus the adult
subjects were successful at modifying their perception of VOT. Pisoni et al. also argued
that the key to this successfirl training was to provide immediate feedback during training

tasks. Further, McClaskey, Pisoni and Carrell (1983) also showed that knowledge about

23

VOT perception gained from laboratory training was genuinely acquired in that the result
of discrimination training on one place of articulation (e.g., labial) was transferred to
another place of articulation (e.g., alveolar) without any additional training.

Another speech contrast that has been investigated in a great detail by a number
of studies is the /r/-/l/ contrast in English. The contrasts are harder for learners to acquire
than VOT distinction. In order to distinguish between /r/ and /l/ in various phonetic
environments, processing of complex temporal and spectral changes is required, although
the stop voicing involves only a temporal difference. Voicing may be more discriminable
to listeners than the acoustic cues that underlie other speech contrasts, since it is
psychophysically more distinctive or robust (Pisoni, Lively & Logan, 1994).

A series of studies was conducted by Pisoni and his colleagues to address the
problems experienced by L1 Japanese learners of English as a second or foreign language.
Japanese does not have the /r/-/l/ contrast (Bradlow, Akahane-Yamada, Pisoni & Tohkura,
1999; Bradlow, Pisoni, Akahane-Yamada & Tohkura, 1997; Lively, Logan & Pisoni,
1993; Logan, Lively & Pisoni, 1991; Pisoni, Lively & Logan, 1994). The training
procedure and stimuli used in their experiments were designed to avoid some of the
problems found in Strange and Dittmann’s (1984) study. In Strange and Dittmann,
although discrimination performance improved gradually over the training sessions, the
effects of discrimination training did not generalize to naturally produced stimuli. One of
the causes of their failure to train learners’ linguistic ability was that the variability of the
stimuli was too limited to generalize, since the training stimuli consisted of only one
/r/-/l/ minimal pair produced by one synthetic voice. Based on this observation, Pisoni

and colleagues used a wider variety of training stimuli, which consisted of natural speech

24

tokens instead of synthesized speech, and minimal pairs in difl’erent phonetic
environments produced by five different talkers. In doing so, they considered the
important role of stimulus variability in perceptual learning. In addition, a two-alternative
forced-choice identification task was used instead of a discrimination task. An
identification task encourages classification of stimuli into categories, while a
discrimination task focuses perception only on fine within-category acoustic differences.
This high-variability training approach for perceptual learning contributed to
generalization to novel stimuli and talker’s voice. Lively, et al. (1993) showed that
increasing the stimulus variability during learning was effective in the development of
robust phonetic categories. The training was also effective in promoting long-term
retention of learning in both perception and production; the Japanese subjects in Japan
maintained their improved levels of performance three months after the perception
training (Bradlow et al., 1999).

Another training technique was described in Jamieson and Morosan (1986).

Their study examined the ability to identify the American English fricatives /6’/ and /6/.

Training was given to Canadian francophone speakers by using a perceptual fading
technique, in which stimuli were presented sequentially from the most acoustically
distinct stimuli to the least distinct stimuli. In a more recent study, McCandliss, Fiez,
Protoppapas, Conway, and McClelland (2002) used a similar technique called adaptive
training to train Japanese learners to acquire the English /r/-/l/ contrast through synthetic
stimuli, which maximally exaggerated the acoustical difference between the contrasts,
and gradually minimized the difference to approximate that found in natural exemplars.

They also investigated the effect of feedback, comparing the presence and absence of

25

feedback in combination with the different types of training. It was found that
combination of adaptive training and feedback facilitated learning the most by calling a
subject’s attention to the critical cues that distinguish the training stimuli. In addition, the
result of the training experiment indicated that the exaggeration effect would increase the
likelihood that the subject would be able to generate consistent labels of contrasts even in
the absence of feedback. However, they also suggested that, as similarly implied by
J amieson and Morosan’s result, what the subjects have learned is a very general
phonological discrimination, and it could not apply to all instances of /r/ and /l/ spoken in
all possible contexts by all speakers. They assumed that the fixed training with a large
number of various stimuli in combination with feedback such as was used by Pisoni and
colleagues in the study mentioned above would lead to more robust generalization and
contribute to mitigating the difficulty learners have in acquiring the target contrast from
natural experience, although their adaptive technique would provide more rapid learning.
While many training studies predominantly used auditory presentation methods,
Hardison (2003) also used and extended the high-variability training approach to include
training in combined auditory and visual modalities. Her study was the first published
study that investigated auditory-visual vs. auditory-only training for L2 learners. Using a
talker’s face, including articulatory gestures, as a visual cue, and locating the sound in
various phonetic contexts and positions within the word, Hardison examined the effect of
speaker and context variability on the perception of the English /r/-/l/ contrast by
Japanese and Korean learners of English. The result demonstrated significant interactions
of these variables and indicated both generalization to novel stimuli and production

improvement. The effectiveness of multimodal training in addition to high variability of

26

stimuli was also observed in the earlier identification of words beginning with /r/, /l/, /p/
and /f/ by Hardison (2005b). As another effective way of providing audio-visual training,
a real-time computerized pitch display was used to provide prosody training for
English-speaking learners of French (Hardison, 2004) and Chinese-speaking learners of
English (Hardison, 2005a). The learners could visualize their own pitch contours in
utterances in the target language and compare it with native speakers’. This is another
example of effective training utilizing visual input along with auditory input to facilitate
learning.

According to Hardison (2000, 2003), these results, that a multi-modal,
high-variability perceptual training approach facilitates learning and generalization,
indicate that language learners store detailed individual instances as memory traces,
rather than creating abstract prototype categories, and use these stored detailed episodes
for memory encoding.

Traditional view of the learning process, known as the abstractionist view,
assumes that any representations of the sound patterns of words are stored as abstract
prototypes and are normalized with respect to variables affecting the sounds, such as the
talker’s voice, speaking rate, and so on. It is assumed that these variables, which were not
necessary for processing the meanings of any given utterances, were discarded as noise
somewhere during speech processing.

The alternative view, the episodic view, does not assume such normalization or
prototype formation, but assumes that listeners store specific instances or tokens in
memory. During processing, they evoke specific instances, rather than abstract

representations of the sound patterns of words, and try to match new instances to these.

27

This view is supported by empirical studies of adult learners (e. g., Goldinger, 1997 ;
Johnson, 1997) and the investigations regarding adults’ and infants’ retention of specific
details of particular instances of perceptual experience, e. g., recognition of particular
voices (Jusczyk 2000). Multiple-trace theory incorporates the above-mentioned prototype
and episodic views of perceptual processing, such as in the Minerva 2 model by
Hintzman (1986), and explains how repetition affects episodic memory. The model
assumes that each experience event has it own memory trace as an episodic trace and
stores specific events in primary or short-term memory (PM) as collections of primitive
properties that include perceptual details, context, affect, semantic connotation, and so on.
When retrieving a memory trace, a retrieval one or “probe,” which is an active
representation of experience, is simultaneously sent to communicate with all stored
dormant traces in secondary or long-terrn memory (SM). When the probe is sent from PM
to all traces in SM, PM receive a single reply or “echo.” Repetition of the same
experience produces multiple traces of an item but does not cause strengthening of a
single memory trace. Each trace reacts more or less intensely depending on its similarity
to the probe, and the contribution of traces which are the most similar to the probe is
greater because they produce a more intense response. If the information in the
representation is more detailed, the probe becomes more specific, which produces a
smaller set of highly activated traces. Thus the responses or echoes to the probes vary in
their intensity and content. Whenever several traces are very strongly activated, the
intensity of content of the echo is very strong and reflects their high level of common
properties; therefore, if a new instance is very similar to previously stored traces, the

intensity of the echo reflects more common properties. A strong echo reflects greater

28

degree of similarity in activated traces and familiarity to the experience. However, if the
probe resembles only a few of the previously stored traces, the returned echo should
reflect more idiosyncratic properties of those activated traces. Thus, the specificity of the
probe and, the number of strongly activated traces will determine whether the echo
content is ambiguous or clear.

Jucszyk’s (1993) development model reviewed earlier is also based on the
episodic view. During the course of perceptual development, the output of the innate
auditory analyzers at an earlier stage of development is weighted to give prominence to
the critical distinctive features in the target language to enable the learner to recognize
words. Through this attention weighting scheme, sound pattern extraction is made, and
then the matching process occurs. The representation obtained through linguistic
experience and by the weighting scheme serves as a probe that will try to be matched
against existing representations, or traces previously analyzed and stored in SM. If a
close match is obtained between the probe and the stored items, the input is recognized; if
not, the input is stored as a new item. It is also assumed that representations of the sound
structure of a word are not stored in the form of abstract descriptions such as abstract
prototypes; rather, the sound properties of items actually encountered in different contexts,
in other words, multiple traces of individual instances of the item are stored.

The above episodic views on the learning process are consistent with the results
from the previous L2 training studies whose results indicate that repetition of
high-variability stimuli and immediate feedback are indispensable factors in effective
training. Hardison (2000) proposed a scenario of bimodal L2 speech processing and the

role of training, based on multiple-trace theory, Jusczyk’s model of child L1 development,

29

 

and results from her auditory-visual resulted in Hardison (1998). The following is her
proposal: at the first stage of L2 acquisition, auditory and visual inputs are preliminarily
analyzed through different pathways. In the next stage, a new weighting scheme for L2
must be developed, so that learners can alter their attentions from the optimal setting to
perceive distinctive features in L1 to the optimal setting for L2 by learning to attend to
new sources of information obtained through the auditory analyzers. For example, to hear
the distinction between /r/ and /l/, attention has to be shifted auditorily to the F3 transition
and visually to the articulatory gestures in order to distinguish between the sounds.
Learning occurs through copying the features of an experience into a trace. Probes, or
signals processed in PM, activate dormant stored traces in SM, and the weighting process
occurs according to the trace’s similarity to the features of the probe, which ultimately
will return an echo to PM. Attention to auditory and visual attributes of the stimulus will
determine the features of the probe. Training with multiple exemplars and immediate
feedback enhance learning; repetition and feedback can direct attention to
within-category similarities and between-category distinctions in L2, adding traces to
memory and modifying the memory system. Old traces are not altered, but new traces are
added. As the result of learning, new L2 memory traces become less ambiguous and less
confusable. Thus, the objective of training is “to create a situation in which the echo from
an aggregate of L2 traces acting in concert overshadows the echo from L1 traces”
(Hardison, 2000, p. 321). The advantage of prototype is its long retention, while
exemplars may be forgotten over time, but decaying multiple-traces of each exemplar
with redundancy can also be reduced. Through many new exemplars in perceptual

learning, learners store multiple traces which mach the probe; these multiple traces share

30

common features, thus firnctioning like a prototype.

Another important feature of Hardison’s (2000) model of L2 development, a
weighting scheme is required to direct learners’ attention to critical distinctive features in
L2. Multiple-trace theory is based on the assumption that all items that are attended to are
stored in memory; learners must be able to attend to critical features of input for
categorization and identification of new L2 contrasts. Multiple exemplars, immediate
feedback, and repetition add traces and increase the salience and information value of
important features to focus on, and consequently enhance learning.

Not all tokens in the target language are equal candidates for incorporating into
the phonetic category, and only those tokens that are perceived during a “signal-oriented”
mode can be collected for incorporation and subsequent modification of a phonetic
category (Lindblom, Guion, Hura, Moon, & Vlfrllerman, 1995). Signal orientation, which
is the cognitive mechanism of attention, helps to create novel categories in addition to the
modification of existing categories. Nosofsky (1986) argues that in categorization and
identification of newly encountered stimuli, selective attention process is assumed to
operate, which leads to systematic changes in the structure of the perceptual space and
changes inter-stimulus similarity relations. Attention weights act to shrink or expand the
perceptual space; the psychological space is stretched along the dimension that is
selectively attended to, maximizing within-category similarity, and is shrunk along the
other dimensions, minimizing between-category similarity, so that learners are optimizing
similarity relations for the given categorization problem. If selective attention properly
modifies similarity relations across the identification and categorization paradigms of

stimuli, the probe to memory will provide good matches to stored L2 traces, returning

3]

less ambiguous echoes to PM, and categorization will be enhanced. Therefore, it is
necessary to direct learners’ attention to focus on the critical properties.

Based on Nosofsky’s proposal, Pisoni, Lively & Logan (1994) examines adult
phonetic processing and concludes that the cognitive structures created by attentive
processes are adjusted from prior linguistic experience and can be modified through
training for better discrimination of non-native phonetic contrasts. As we have reviewed,
training programs with high variability and multimodality have shown their effects in the
shifting of learners’ focuses, which leads to generalization to new tokens they encounter
in the real world. Empirical studies have reported that different sensory areas affect other
classification learning in the individual modalities. Bimodal speech recognition reported
by McGurk and MacDonald (1976) showed that a pair of auditory and visual stimuli (the
visual stimulus being a speaker’s lip movement) can affect each other and produce a
sensory effect different from either the actual auditory input or the visual input. de Sa and
Ballard (1997) argued that responses of cortical cells in the primary sensory modality
would respond to features from other sensory modalities. They then proposed a
computational model using the information in one modality to modulate learning in
another, instead of merging the outputs from different pathways. In perceptual learning in
SLA, not only auditory input but also visual input in AV-training, such as described in
Hardison (2003), facilitates such processes. Based on these observations and the
exemplar—based theory of learning, the current study also aims to give beginning learners
of Japanese effective training to accurately perceive geminate consonants through
multimodal (not only auditory, but also visual) training, with a variety of stimuli and

immediate feedback, expecting better improvement than that resulting from auditory-only

32

training, as well as generalization to novel stimuli.

Some studies have shown that there is a close link between perception and
production through demonstrating transfer of training, in which the effect of training on
one domain was transferred to another. In Bradlow, Pisoni, Akanae-Yamada, and Tohkura
(1997), 11 Japanese learners of English received 45 sessions (30 minutes each) of
perceptual identification with feedback over 15 days. The stimuli consisted of minimal
pairs for /r/ and /l/. Although the training was designed only for perception, the pretest
and the posttest included assessment of production ability. The result showed that the
subjects improved not only in perception but also in production. In Rochet (1995), native
speakers of Mandarin Chinese received perception training for French voiceless stops,
and the result also showed that improvement in perception performance could carry over
to improvement in production. In addition, a similar transfer effect was found in the
studies on phonologically delayed children conducted by Jamieson and Rvachew (1992).
Their studies also showed that speech production treatment for the children benefited
from perception training.

A very early training experiment in production showed a similar transfer effect;

i.e., the effect of production training carried over into perception performance. Catford
and Pisoni (1970) compared the performance of subjects who received production and
articulation training involving unfamiliar or “exotic” sounds and that of those who were
trained only in perceptual discrimination. The results of production and perception tests
showed that those who received articulation training in addition to perceptual training
performed better. This finding implied, as they suggested, “some kind of carry-over

from productive competence to auditory discriminatory competence” (p. 481); thus,

33

improved production abilities may contribute to better discrimination. of L2 sounds.

Leather (1990) conducted two experiments in parallel with two different groups
of Dutch learners of Mandarin Chinese; perception tests were given to the subjects who
had been trained only in the production of Chinese tones, and production tests were given
to those who had received only perception training for the same tones. The progress that
the two groups made was compared, and the results showed no difference in their
progress. Both groups improved at the same rate. He argued that his subjects “did not
need to be trained in production to be able to produce, or in perception to be able to
perceive, the sound patterns of the target system” and “training in one modality tended to
be sufficient to enable a learner to perform in the other” (p. 95).

The bimodal (audio and visual) training of Hardison (2003) also showed
improvement in subjects’ production ability. Hardison suggests that L2 learners may
“attempt to coordinate information about perception and production in category
development” (p. 516), a claim similar to that made by Jusczyk’s model (1993) of L1
development. Interactions between the developing perception and production systems
may afl’ect the way learners acquire knowledge of L1 sound patterns. Learners are under
pressure to coordinate the way that these systems function and to relate the perceptual
representations of words to the articulatory representations for production, so they may
reach an abstract representation to capture generalizations that apply to both systems,
which is phonology. It is the coordination of perceptual and productive representations
that may lead the language learner from a more global representation of sound patterns of
words to one that is structured with respect to phonetic segments. According to Jusczyk,

when infants start babbling, they are very attentive to the distinctive features of the

34

language. Production development lags behind perception since infants have to wait until
they gain control and coordination over their jaw movements; it also takes time to
coordinate information from both modalities. Adults learners do not have to wait for the
development of their articulatory system, but it is observable that they also need some
time for the coordination of both modalities. At the same time, it should also be noted that
production is more easily altered through formal instruction, as has already been

mentioned.

'9'”: 1&5

On the other hand, differences in the rate of development in perception and
production were found in Bradlow et al. (1997), who reported little correlation between
degrees of learning in perception and production after perception training. The learners
who improved the most in perception did not necessarily improve the most in production.
There was variation in learning; degrees of learning in perception are difl’erent from the
transferred learning in production. They noted that “learning in the perceptual domain is
not a necessary or sufficient condition for learning in the production domain; the
processes of learning in the two domains appear to be distinct within individual subjects”
(p. 2393. This claim is compatible with the results of Akahane-Yamada (1999). As
Bradlow et al. (1997) indicated, their study did not support Flege’s (1995) SLM. The
SLM assumed that improvement in speech production as a consequence of perceptual
learning is due to a reorganization of the underlying system used for both speech
perception and production and hence, predicts that changes in perception will transfer to
changes in production, and these changes will proceed in parallel. However, the SLM
does not account for the results of Bradlow et a1. (1997), which indicated the presence of

individual variations in learning and the lack of correlation between degrees of learning

35

in the two domains.

The specific relationship between production and perception is not clear; they
might differ according to sound types, phonetic contexts, methods of data collection and
training, and so on. However, most of these studies agree on the following; 1) perception
ability and production ability are closely related: though the degree of correlation is not
clear, the abilities do not appear to develop independently; 2) training experiments bring
apparent improvement to adult learners, either in perception or production, or both.
Therefore, it is possible to train adult learners to perceive and/or produce novel phonemes
in the L2, though training methods and data collection processes in the above-cited
studies varied.

The above-reviewed training studies demonstrate the adaptability of the adult
perceptual system through training, and there is a certain relationship between perception
and production. There have been a number of studies involving various L1 8 and L25, as
well as various kinds of segments (vowels and consonants) and suprasegmentals (e. g.,
Chinese tones); however, very few studies have been conducted in this context to
examine geminate consonants in Japanese. The present study took as one of its principal
objectives the investigation of the relationship between the acquisition of the perception
and the acquisition of the production of geminate consonants, in particular, the

contribution of perceptual training to productive ability.

2.4 Making visual information available to L2 learners

2.4.1 Electronic Visual Feedback (EVF)

The previous section reviewed some previous laboratory training studies. In this

36

 

section, alternative ways of improving learners’ perception of geminate consonants will
be considered. A growing number of language programs have been utilizing recent
developments in the technology available as computer-assisted instruction for perception
and pronunciation training to enhance self-monitoring skills by learners. For example,
electronic visual feedback (EVF) is a type of computerized training which utilizes
software (e.g., Cool Edit by Syntrillium Software, Wavesurfer, and Praat) or hardware
(e. g., Computerized Speech Lab (CSL) and Visi-Pitch by Kay Pentax and IBM Speech
Viewer) to perform an acoustic analysis of a target sound. Chun (2002) used Speech
Tools, downloadable web-based software provided by SIL, for the images of intonation in
her book. Speech Analyzer, a component of Speech Tools which offers visual analyses
such as waveform, pitch plot, spectrogram, spectrum and various F1 vs. F2 displays. All
these programs and devices involve the digitization of speech and its subsequent visual
representation on a video screen. Such technology allows learners to measure and
visualize intensity, duration, frequency range, etc. of the target sounds. Researchers have
reported the effectiveness of such training in improving learners’ perception and

production.

2.4.2 Effects of instruction on production of segments and suprasegmental features
Molholt (1988, 1990) reported effective use of EVF when teaching difficult
consonants and vowels to Chinese ESL students in laboratory sessions using Kay Pentax’
Visi-Pitch and Speech Spectrographic Display (SSD). With Visi-Pitch, students can see
simultaneously both an instructor’s and their own spectrograph and waveform of a target

sentence to practice. In general, the energy concentration of Chinese consonants has a

37

higher frequency than that of American consonants. The differences in the duration of
American /v/ and /b/ are new to Chinese speakers. Molholt (1988) introduced EVF as an
effective way to teach segments through the visual representation of frequency (including
voicing), aspiration, and duration of such difficult consonants. For example, as for
frequency, since Chinese has no voiced stops and only one voiced fricative, the language
in general has a higher frequency range than English. Therefore, it is important at the
beginning of pronunciation lessons for Chinese students to start building more sensitivity
to sounds in the low-frequency range. EVF enables teachers to provide students with
visual instruction on how to control frequency, such as in a minimal pair for /s/ and /z/.
The visual display provides an objective measure that helps students focus their attention
on the exact features of their pronunciation that need to be changed. This technique is
also used in teaching vowels.

Many researchers have reported that EVF has been used by ESL learners for
teaching various aspects of suprasegmental features, such as stress, rhythm, and
intonation (e.g., Anderson-Hsieh, 1994, 1996; Chun, 1989, 1998, 2002; de Bot, 1983;
Hardison, 2004, 2005b; Levis & Pickering, 2004; Molholt, 1988, 1990; Weltens & de Bot,
1984). Anderson-Hsieh (1994, 1996) also reported advantages of EVF in teaching
suprasegmental features. On listening to spoken discourse, her ESL learners only focused
on individual lexical items, and they tended to ignore the accompanying rhythm of
utterances. In addition, a more serious problem was that they did not notice the
importance of perceiving these suprasegmental features, so that they tended to have
difficulty producing them.

By providing visual information about suprasegmental features in real time, it

38

“2*

becomes possible to raise learners’ awareness of such speech characteristics, as well as
providing an effective training procedure. For example, one of the typical problems that
Japanese ESL learners have is transfer of their L1 rhythm, which is a “mora-timed
rhythm,” and their failure to highlight stressed syllables sufficiently because they use
pitch accent instead of stress. Anderson-Hsieh (1996) used EVF in her classroom
instruction. While EVF provided visualizations of the difference between the native
speaker model’s and students’ own speech, the students were encouraged to repeat the
words, make greater differentiation in length between stressed and unstressed syllables,
and use higher pitch on the stressed syllables. She also reported that EVF was effective
not only for word-level stress, but also sentence-level stress and intonation. Levis and
Pickering (2004) also reported the use of speech visualization technology in teaching
intonation at the discourse level. They claimed that providing practice with
discourse-level intonation features is the next step in using technology for the teaching of
intonation, so that learners can learn to use intonation for real communicative needs. For
teaching prosody, Hardison (2004) also used a computer assisted speech training program
by Real-Time Pitch (RTP) along with Kay Pentax Computerized Speech Lab (CSL),
which displays simultaneously both of an instructor’s and a learner’s pitch contours for
comparison, to teach French prosody to English speakers. In addition to RTP, in Hardison
(2005a), Anvil, a web-based annotation tool integrating the video of a speech event with
its pitch contour display was used to teach English prosody to Chinese speakers. For
learners of Japanese, Landahl, Ziolkowski, Usami and Tunnock (1992) and Hirata (1999,

2004) reported effectiveness in teaching Japanese pitch contours using Visi-Pitch with

CSL.

39

 

2.4.3 Experimental studies of EVF

Although their number is limited, several reports on studies of EVF have
provided relevant experimental information concerning the number of subjects, statistical
analysis of data, etc. de Bot (1983) conducted an experiment to assess the influence of
auditory-visual feedback vs. solely auditory feedback on the learning of English
intonation. The subjects in the experimental group were presented with a sentence
through headphones. The F0 contour, i.e., pitch, of this sentence was plotted on a display,
and then they had to imitate the sentence as their own F0 contours appeared on the
display for comparison. In the experiment, practice time was another factor: one group
received only one training session of 45 minutes while two sessions were provided for the
other group. The control group followed the same procedure, but without visual feedback.
The result of the experiment showed that visual feedback produced a significant effect on
the learning L2 of intonation, whereas practice time was not a critical factor. In other
words, optimum imitation of a sentence was reached sooner with auditory-visual
feedback than with auditory feedback only. One of the advantages that de Bot pointed out
was that the use of this kind of equipment tends to increase the subjects’ motivation to try
harder to achieve their learning target.

In Hardison (2004), 16 American learners of French received three weeks of
training in French prosody using computerized displays of pitch contours as visual
feedback. The results revealed significant effects of training in the acquisition of prosody.
In addition, generalization to segmental accuracy and novel sentences was also found.
Thus, the efl’ect of training is apparent not only in the immediate focus of the visual

feedback but also in novel tokens. Hardison’s observation of the learners during sessions

40

suggested that there appeared to be a hierarchy of the learners’ awareness, fi'om more
global elements such as the pitch contour, which was the focus of visual feedback, to
more local elements such as individual sounds.

Further, Hardison (2005a) conducted prosody training with Chinese learners of
English using a web-based annotation tool integrating the video of a speech event with
visual displays showing the pitch contours and examined the effects of discourse-level
input versus sentence-level input. The presence of video was more helpfiil with
discourse-level input than with individual sentences. Here again, high variability of the
stimulus was effective in combination with auditory and visual input sources.

However, as Anderson-Hsieh (1996) pointed out, EVF has some drawbacks, too.
The major disadvantage of EVF is that the commercial hardware may be too costly to use
in language laboratory settings and for individuals, e. g., it may be too costly to purchase
Kay Pentax products. It is also not convenient for use in large classes except for
demonstration. However, there are a number of free or low-cost programs available for
use as “e-learning” tools (e. g., Praat, SIL Speech Analysis software WaveSurfer). Another
point that should be considered is that instructors need to acquire technical knowledge to
read some types of visual displays, and their careful control of the information in guiding
students is indispensable.

As we have seen, there are many studies reporting on the use of EVF to improve
learners’ production of segments (vowels and consonants) and of suprasegmental features
(e. g., tone, stress, and intonation). This present study examined the possibility of using
EVF for enhancing the learning of durational contrasts, mainly related to geminate

consonants in Japanese, through the display of waveforms, which make duration visible,

41

as discussed in the following chapter (Experiment II). Further, EVF so far has been used
mainly to train learners’ production ability, and few reports have addressed perception
improvement. As seen in the previous section, a number of studies concluded that gains
from perception training in L2 contrasts can transfer to productive ability. In light of the
previous studies of the effects of EVF, the present study explored the potential of visual
input for both perception training and production learning of Japanese geminate

consonants by American learners of Japanese.

2.5 Research questions and hypotheses

The present study was motivated by the following research questions and
hypotheses:

1) How do L2 learners perceive and produce geminate consonants? Is there any
particular phonetic context of geminate consonants, which makes perception and/or
production more difficult for learners?

Many previous studies of geminate consonants have been conducted on native
and normative speakers, but few studies have focused on the effect of the types of
consonants and of phonetic contexts. I hypothesized that the learners’ perception and
production would be affected by phonetic environments, and this might be a cause of
difficulties in acquiring the contrasts. The present study aimed to find if there are any
particularly difficult contexts for learners. While previous studies which examined
learners’ perception and production used only words in isolation as stimuli, the present
study also examined whether there was any difference between word-level and

sentence-level performance, as either of these levels might constitute a difficult context

42

for the accurate perception and/or production of geminate consonants.

2) Are audio-visual instruction and training using visual displays of waveforms of
geminate consonants more beneficial than auditory-only information?

Coupled with the results of the above research question, this study aimed to find
an effective method of perceptual training. The effectiveness of visual input in addition to
audio input in perceptual training has been reported by previous studies (e.g., Hardison
2003), so it was suggested that it was also effective in training learners in the perception
of geminate consonants. Based on the results of the previous studies, and as a possible
application of the theory of episodic memory (Hintzman 1986), I hypothesized that the
perceptual training with visual information would also be successful in guiding learners’

attention to critical durational contrasts; thus, the training would be more effective.

3) Does perceptual training improve production ability without any explicit production
training?

Previous studies have suggested the relationship between perception and
production and reported production improvement through perceptual training of /r/ and /l/
contrasts (e. g., Akahane-Yamada et al., 1996). This research hypothesized that the
perceptual training with visual input would also lead to development in the ability to
produce geminate consonants; therefore there was a close link between perception and
production would be demonstrated. The participants in this study were given only
perceptual training, but they were given production tests to examine whether their ability

to produce geminate consonants improved at the same time.

43

CHAPTER 3

Experiment I

3.1 Overview of the experiments

In the present study, a total of four experiments were conducted. The subjects
were all native speakers of American English who were studying Japanese at the
university level. Experiments 1 through HI concerned the difficulties that the learners
encountered with regard to geminate consonants. Experiment I and Experiment HI were
conducted to obtain perception and production data, respectively. Considering the
learners’ difficulties found in Experiment 1, Experiment H was conducted as a pilot study
to test electronic visual input as a method to improve their perception. Based on the
findings of these three experiments, a training method was explored, and Experiment IV

was conducted to test the effect of the training.

3.2 Objectives of Experiment 1

Many of the previous studies of geminate consonants limited the test items to
stops and did not refer to the types of geminates tested and their phonetic contexts. This
study aimed to examine if there are any particular phonetic contexts for and identities of
geminate consonants that make perception more difficult for learners. Through detailed
examination of such conditions, the research question of Experiment I is thus to find what
causes the learners’ difficulty in perceiving a particular type of geminate consonant. As
discussed above, the closure duration of stop geminate consonants produced by native

speakers varies depending on the identity of the consonant itself, and this may affect

44

non-native speakers’ perception. Furthermore, consonant types other than st0ps should be
considered to see if there are any particular consonant types and phonetic conditions in
which learners find it difficult to distinguish a singleton from a geminate consonant.
First, I hypothesized that one of the causes of difficulty in acquiring accurate
perception of geminates was related to the sonority of the target segments. Previous
studies reported that there was no effect on the perception of Japanese geminates of the
following vowel for native speakers (Hirato & Watanabe, 1987). However, there may
be some effect on learners’ perception resulting from the identity of the vowel (/a/, /i/, /u/,
/e/, or /o/) that follows a geminate consonant (Minagawa & Kiritani, 1996). In order to
see if there was any effect of the following vowel on the perception of a geminate
consonant, /a/ and /u/ were selected. These two vowels have different levels of sonority
according to a scale which is considered universally applicable. Sonority is a ranking on a
scale that reflects the degree of openness of the vocal apparatus during production, or the
relative amount of energy produced during the sound (Goldsmith, 1990). The sonority
hierarchy is generally described as having the organization shown in Figure 3.1. Japanese
has a five-vowel system, which consists of /a/, /i/, /u/, /e/, and /o/. Between the two
vowels selected for this experiment, /a/ has the highest sonority and /u/ has the lowest

sonority.

45

 

Most sonorous it Vowels
low vowels e.g., /a/

mid vowels
high vowels e.g. /u/
flaps
laterals
nasals
fricatives
affricates

Least sonorous stops

 

Figure 3.1. Sonority hierarchy (from Goldsmith, 1990; p.110)

Thus, it was also examined how the sonority of the following vowels would affect the
learners’ perception of geminate consonants. Since hierarchies do not indicate an actual
degree of distance, Selkirk (1984) proposed the quantification of sonority in a Sonority

Index as shown in Figure 3 .2. The higher the number is, the greater its sonority.

 

 

 

a e,o i,u r 1 m,n s v,z, f,0 b,d,g p,t,k

 

Figure 3.2. Sonority index (Selkirk, 1984, p. 112)

In addition, according to this index, in bisyllabic words, the sonority distance between a

46

 

geminate consonant and the following vowel is closer in a fricative (e. g., in sassa) than
when it is a stop (e. g., in sakka). The bigger difference might help to perceptually
highlight the boundary between the geminate consonant and the following vowel, aiding
speech perception (Kenstowicz, 1994), while the closer difference might obscure the
boundary between the consonant and the vowel. Highlighting the boundary between the
geminate consonant and the following vowel would make the precise duration of the
geminate easier to perceive. Thus, it could be predicted that the learners would have more
troubles with perceiving words containing an /ss/ fricative geminate consonants than
those containing a /kk/ stop geminate.

Another hypothesis is that English, the learners’ L1, may play a role in
determining their ability to perceive a geminate consonant in Japanese to some extent.
English has a constraint called the Maximum Onset Principle in syllabification; it says
that intervocalic consonants should be syllabified into the onset of the second syllable
rather than the coda of the first syllable. Thus consonants are preferred in the onset
position, while no coda consonants are preferred except in the word final position
(Goldsmith, 1990). According to this principle, the preferred syllabification of VCCV is
V.CCV rather than the syllabifications VCCV or VCCV. Since the L1 of all the
participants of this study is English, they might determine a syllable boundary by
following this principle. It could be predicted that if a learner failed to perceive the mora
weight (two morae for a vowel plus a geminate consonant) correctly, s/he might have a
bias toward assigning the consonant as part of the onset, so that s/he might perceive a
geminate consonant as a singleton as CV.CV. If the entire geminate is syllabified as part

of the onset, then it cannot have moraic weight (Hayes, 1989), that is, it cannot be a

47

geminate.
For ease of exposition, following Kenstowicz’ (1994) and Hayes’ (1989)

description of moraic syllable structure, geminate and nongeminate consonants are
represents as follow (syllable: o ; mora= [1 ). For example, in a CVC monosyllabic word

in English, the vowel in nucleus is assigned one mora and consonants in onset and coda

positions are nonmoraic as shown in Figure 3.3.

o
/ I\
p .' .

Figure 3. 3. CVC word (e. g., “pet” in English)

On the other hand, the first part of a geminate consonant is moraic. For example, the
Japanese word /sakka/ containing a geminate consonant is syllabified as a trimoraic

bisyllabic word as shown in Figure 3.4.
c\ 0

/ii i1 / u

s a k a

Figure 3. 4. CVC.CV word (e. g. “sakka” in Japanese)

It has been suggested that the syllable plays a important role in the processing of speech

48

1‘51" _.___ I

sound segments (e. g., Derwing, 1992; Ishikawa, 2002; Mehler et al., 1981; Schiller,
Meyer & Levelt, 1997). In Japanese, morae as timing units have to be processed in
addition to syllables, which may cause difficulties for L2 learners.

As another possible source of difficulty for learners, the question of whether there
is any difference in identification accuracy for geminates in words in isolation as opposed
to those embedded in sentences was examined. Traditionally, the dominant method for
examining learners’ development of the ability to perceive new, difficult nonnative
contrasts has been to use a two-alternative identification or discrimination task with
minimal pairs in isolation. For example, many studies use a two-altemative identification
task; the learners are presented with stimuli consisting of minimal pairs for /l/ and /r/ in
isolation (Bradlow et al., 1997; Bradlow et al., 1999; Hardison, 2003; Lively, Logan, &
Pisoni, 1993; Pisoni, Lively, & Logan, 1994). With regard to the present study, Minagawa
(1996), Hayes (2002), and Min (1993) all used a two-altemative identification task,
having the learners identify minimal pairs for single/geminate consonants in isolation. A
question raised here is whether a two-altemative forced choice task using minimal pairs
in isolation is sufficient. Would the results reflect the overall perception ability of learners
in a variety of phonological contexts? In actual conversations, learners have to identify
phones or sounds and syllables in a flow of sounds, a longer and more complicated
context than that of words in isolation. Is there any difference in learners’ perception at

the sentence level?

49

3.3 Method
3.3.1 Participants

All participants were undergraduate students at a large university in the US, and
all were native speakers of American English whose ages ranged 19 though 22. There
were no heritage learners. They were divided into three groups on the basis of the level of
the Japanese courses in which they were enrolled at the time of the data collection. The
101 level group was made up of students in first-year Japanese language courses at the
university (n=28; 7 females and 21 males). The students enrolled in the 101 level had
almost no previous knowledge of Japanese, and it had been about three months since they
had begun to study the language. The 201-group of students in the second-year Japanese
language courses (n=42, 17 females and 25 males) was composed of those students who
had passed the first-year class in Japanese. It was the third semester for these students.
The 401-group of students in fourth-year Japanese (n=15; 5 females and 10 males) was in
their seventh semester of studying Japanese. All the 401-level learners had studied in
Japan for one or two semesters. Generally, it can be said the 401-level students had had
more interactions with native Japanese speakers than had the students in the other lower
levels, although this did not guarantee that they had become proficient proportionally,
since the learning opportunities, motivations, and L2 uses of Japanese varied among the
students. In the regular introductory Japanese classes, the first- and second-year courses,
the students met for 50 minutes, 5 times per week. There were substantial oral drills and
communicative activities in class, and the instructor sometimes corrected the students’
inaccurate pronunciations. However, there was no special training for discriminating

particular phonemic contrasts in class.

50

 

3.3.2 Materials

Stimuli consisted of 30 bisyllabic Japanese real words and non-words, which
included 12 singletons, with the segmental form /(C)V.CV/, and 12 geminate counterparts,
with the segmental form /(C)V.C.CV/, where the first CV and the final CV were identical,
and 6 fillers which were bisyllabic words consisting of three morae, but including no
geminate consonant. As defined in 2.1.1, a mora is a unit of timing, and each mora has
approximately the same duration in production. Long vowels (e.g., /kiite/ ‘listening’) and
geminate consonants (e. g., /kitte/ ‘a stamp’) take twice as long to produce as a short
vowel or singleton counterpart (e. g. /kite/ ‘coming’).

Two tests were conducted; in Test 1, the words were heard in isolation, but in Test

2, the following carrier sentences were used.

watashi wa to iimashita
I topic that said

marker

‘1 said .’

kore wa desu

this topic is
marker

‘This is .’

Note that as the word-for-word gloss shows, in Japanese word order, the stimuli come in
the middle of the sentence, instead of the sentence final position seen in the English
translations. The same set of 30 words was used for both tests, but the order of
presentation was randomized.

As for the target consonants, the stops /t/, /k/ and a fricative /s/ were the same

sounds as were used in Hayes’ (2002) study (of. Ch. 2.1.4). In Hayes’ study, learners were

51

presented with a set of two words in each trial, either geminate-geminate,

geminate-singleton, or singleton-singleton combination, and the learners were given a

same-different discrimination task, i.e., they were asked to determine whether the two

words were same or different. Such a discrimination task might not directly reflect

learners’ linguistic perception ability since it is rare to encounter a comparison of two

sounds in a natural setting. In the present experiment, the learners were presented with

only one token in each trial, and they were given an identification task to identify whether ‘
the token was a geminate or a singleton.

Previous studies revealed that the duration of the vowel preceding a geminate
consonant plays a role as an acoustic cue for native speakers, but not for non-native
speakers (Min, 1987), and that variable was therefore excluded from consideration in the
present study. To test for the effect of the difference between /CV/ and N / as preceding
segments, /sa/ and /a/ were chosen as preceding contexts. The vowels following a
geminate consonant were a high vowel /u/ and a low vowel /a/. Since Experiment I did
not consider the effect of pitch accent, the accent patterns of all the stimuli were kept
consistent; they were H(igh)-L(ow) for singletons (i.e., two mora stimuli) and H-L-L for
geminate consonants and long vowels (i.e., three mora stimuli). The stimuli consisted of
14 non-words and 16 real-words. In Table 3.1 below, translations are given for

real-words; non-words are indicated with "".’

52

Table 3.1

Examples of test items by phonological structure

 

Singleton Geminate

 

 

 

/t/ /tt/
/s/ /ss/
/k/ /kk/

 

 

 

 

 

 

Structure of items Example V2=lul Example V2=lal
(C)V1.tV2 (C)V1t.tV2 satu sattu sata satta
‘volume’ * ‘trouble’ ‘went’
(C)V1.sV2 (C)V1s.sV2 sasu sassu sasa sassa
‘stab’ ‘guess’ * ‘quickly’
(C)V1.kV2 (C)V1k.kV2 saku sakku saka sakka
‘tear’ ‘sack’ ‘refreshments’ ‘composer’
3.3.3 Procedure

The above stimuli were recorded by a female native speaker of Japanese (Tokyo

dialect) using a SONY MD MZ-RHlO-S with a SONY ECM-CSIO microphone. The

stimuli were presented on the same mini-disk player in a classroom setting. Each

recorded token was played only once.

A three-alternative forced choice identification procedure was used for the

word-level and the sentence-level tests. The learners were asked to choose from one of

three choices on their response sheets, which consisted of minimal triplets including a

singleton /(C)V.CV/, a geminate consonant /(C)V.C.CV/ and a long vowel /(C)V.V.CV/,

where the first CV and the final CV were identical in each item in the triplet (in the case

of vowel-initial words, the first vowel was the same in each item).

53

Below are the examples of the test items:
The participants heard: /sassu/
Choices given (instructed to circle one):
a. sasu
b. saasu
c. sassu
The participants heard: /aka/

Choices given (instructed to circle one):

a. aka

b. aaka

c. akka

The answer sheets were collected, and correct answers were tabulated for each
participant; if an answer was correct, one point was given, but no point was given for an
incorrect answer. Two types of test were given to each participant, words in isolation and

words in frame sentences as previously described. There was a total of 24 points in each

test.

3.4 Results

The first set of data was scored by totaling the number of correct responses as in
Figure 3.5. A mixed design 2 x 3 ANOVA was used with test (word level, sentence level)
as between-group variable, and with level (101, 201, 401) as within-group variable. Test
and level had significant main effects, F,( 1, 102) = 181.15, p = .000; HQ, 102) = 4.085,
p = .020. The words in carrier sentences produced more errors (56%) than the words in
isolation (75%). The interaction of Test x Level was not significant (F (2, 102) = 1.035, p

= .359), which indicated the difficulty of the sentence-level test as opposed to that of the

54

word-level test was compatible throughout the levels.

Comparison among the levels in a post-hoc test (Tukey’s HSD) revealed that
there was no significant difference between the 101 level (61%) and the 201 level (65%).
However, the 401 level (72%) was better than the 101 level at significant levels (p
= .015) and the 201 level (p = .045). It is assumed that the 401 level students’ superior
performance could also be due to much more exposure to Japanese language through
actually studying in Japan. Over the course of Japanese language study and exposure,
native English speakers learning Japanese develop increased sensitivity to consonant

duration. This result supports the findings of Hayes (2002).

 

 

 

 

Mean % Correct Identification

 

 

 

 

 

 

101 201 401
101 201 401
Word level 71% 75% 80%
Sentence level 50% 55% 64%

 

Figure 3. 5. Mean percent correct identification by level of proficiency

Next, word-level perception and sentence-level perception of geminate

55

consonants were examined in detail separately. A detailed analysis was made of the data
from the 201 level students, which was the largest group of the three. Figure 3.6 shows
the data of word-level perception of geminate consonants followed by /a/ (N=6, M=4.57,

SD=1.70) and /u/ (N=6, M=3.95, SD=1.63).

 

 

CI /+a/
I /+u/

 

 

 

Mean % Correct Identification

 

 

 

 

 

 

/ss/ /tt/ fkk/
/+a/ 73% 77% 83%
/+u/ 51% 64% 73%

 

Figure 3. 6. Mean percent correct identification at word-level by item condition (Japanese

201 students)

A two-factor repeated measures AN OVA was conducted. Variables were
consonant (/s/, /t/, k/) and vowel (/a/, /u/). Both had significant main effects, Fe (2, 198) =
38.500, p = .000; Fv (1, 99) = 46.718, p = .000. The interaction of Consonant x Vowel

was also significant (F (2, 198) = 7.579, p = .001). /s/ consonants were the most difficult

56

to perceive as geminate (73%), while /k/ (83%) was the easiest, and /t/ was in the middle
(77%). As for the vowel following a geminate consonant, the geminates preceding /u/ in
the final position (63%) were more difficult to perceive than those preceding /a/ (78%).
This result may indicate that, as predicted, the sonority of a vowel following a geminate
consonant played an important role in the learners’ perception. Thus, of all the geminate
consonant types, /ss + u/ was the most difficult for the learners to perceive (51%) while

/kk + a/ was the easiest (83%), as shown. In addition, the difference between the effects

 

of /a/ and /u/ was the biggest in following /ss/, while the perception of /tt/ and /kk/
showed almost parallel effects. This result does not support Hayes’ (2002) result, which
showed that there was no difference between lkk/ and /ss/, and that /tt/ was the easiest to
perceive. This discrepancy may be the result of a difference between a discrimination task,
as in Hayes’ study, and the identification task used in the present study.

In addition, there was no significant difference between the scores with /sa/ and
/a/ as the preceding segments (t (299) = -.218, p = .828). That is, the difficulty in
perception was not affected by the difference between preceding segments with
consonant + vowel or with vowel only.

Figure 3.7, which is also a detailed analysis of 201 students’ data, shows

sentence-level perception of geminate consonants followed by /a/ (N=6, M=3. 16,

SD=1.37) and /u/ (N=6, M=2.36, SD=1.47).

57

 

 

 

CI /+a/
I /+u/

 

 

 

Mean % Correct Identification

 

 

 

 

 

 

/ss/ /tt/ fkk/
/+a/ 59% 62% 75%
/+u/ 39% 50% 54%

 

Figure 3. 7. Mean percent correct identification at sentence-level by item condition

(Japanese 201 students)

Again, a two-factor repeated measures AN OVA was conducted, and variables
were consonant (/s/, /t/, k/) and vowel (/a/, /u/). Both had significant main effects, Fe (2,
198) = 32.575, p = .000; Fv (1, 99) = 43. 190, p = .000. As in the word-level perception,
the geminates preceding /u/ in the final position (48%) were more difficult to perceive
than those preceding /a/ (65%). As for the consonant, /s/ consonants were the most
difficult to perceive (49%), while /k/ (65%) was the easiest, and /t/ was in the middle
(56%) as in the word-level data. However, the interaction of Consonant x Vowel was not
significant (F (2, 198) = 1.740, p = .178). Similar difficulty of /u/ compared to /a/ was

observed across the three consonants at the sentence level; /s/+/u/ was the most difficult

58

combination.

In the sentence level, too, there was no difference between the scores with /sa/

and /a/ as the preceding segments (t (299) = -. 173 8, p = .083). Again, the difficulty in

perception was not affected by the preceding segments at the sentence level.

The data in Figures 3.8 and 3.9 show how the learners perceived a geminate

consonant when they did not perceive it correctly, at word-level and sentence-level,

respectively. In order to enable a closer examination of the most difficult item, i.e., a

geminate + /u/, the data are broken down by error pattern. Some of the learners who

could not perceive a geminate consonant correctly tended to think that the word

contained a long vowel. This tendency was especially strong in the /ss + u/ geminate

sequences.

 

103%

Answer Ratio
s§§§§§§§§§

 

/ss/

/tt/

 

/I<k/

 

 

Cl <Geninate>
I Long vowel
E] Sngleton

 

 

Figure 3. 8. 201 students’ perception of /CC+u/ at word-level

59

 

 

 

I

 

D <Geninate>
I Long vowel
Singlemn

 

 

 

 

Answer Ratio
s§§§§§§§§§§

/ss/ /tt/ /kl</

 

 

 

Figure 3. 9. 201 students’ perception of /CC+u/ at sentence-level

Yamagata and Preston’s (1999) study shows an interesting correlation with this
result. They conducted a study to see how English-speaking learners of Japanese acquired
the spelling of English loanwords in Japanese. English loanwords are converted into
Japanese spelling and generally follow the phonological system. This conversion is made
very systematically, and gemination plays an important role. For example, monosyllabic
words of CVC syllable structure with a lax vowel are systematically realized with
gemination of the coda consonant (e.g., pot [potto]), and that is basically how native
speakers of Japanese perceive the English word.

Yamagata and Preston had the learners spell some English words in Japanese to
see how they perceived the English words in terms of the Japanese phonology they were
acquiring and precisely how they conformed them to Japanese phonological rules. The
results showed that the learners often lengthen vowels where native Japanese speakers

spelled the words with geminates. Yamagata and Preston concluded that, although the

60

learners failed to geminate, they still felt the demands of giving the target word the same
number of morae which it would have had if gemination had occurred. Since the spelling
may or may not reflect the learners’ actual production or perception, these results should
be treated with caution. However, this result is compatible with the present findings: even
if the learners in the present study failed to perceive geminate consonants correctly, they
often perceived the geminate consonants as long vowels; hence, they could perceive the
correct number of morae. Since long vowels add the same number of morae as geminate
consonants, it can be assumed that the learners can perceive the mora weight correctly,

particularly in the /ss/ condition.

3.5 Discussion

In Experiment I, it was found that certain types of geminate consonants were
more difficult for the learners to perceive. First, a geminate consonant followed by the
high vowel /u/ was more difficult to perceive than one followed by the low vowel /a/. The
lower sonority of /u/ versus /a/ suggests that the learners may depend on the perceptibility
of the boundary between the second part of the geminate consonant and the following
vowel. Another observation was that a geminate consonant read in a sentence frame was
more difficult to perceive than one read in isolation. This result indicates that the ability
to perceive geminate consonants in isolation does not always guarantee the ability to
perceive them in fluent speech, which the learners will encounter in natural settings.

The learners with more Japanese language experience exhibited a better ability
to identify durational contrasts of single versus geminate consonants. The difference

between adjacent instructional levels (101 and 201 levels) was not significant, but the

61

general pattern of improvement over time is apparent through the upward slope of the
identification accuracy rate. The results are compatible with those of Enomoto (1989),
who also reported that advanced level learners had a clearer perceptual boundary for
identifying geminate consonants, compared to beginning learners. These results also
suggest the possibility of improving learners’ perceptual accuracy.

This result, which showed the subjects’ performance over length of exposure to
Japanese language study, confirmed the result of Hayes’ (2002) study. However, the data
in Figures 3.6 and 3.7 do not support Hayes’ result, which showed that /tt/ was the easiest
to perceive and that there were no differences between the /ss/ and Add conditions. In this
study, /ss/ shows the lowest correct rates — it was the most difficult to perceive. With
regard to the stop consonants /kk/ and /tt/, the sonority distance between the consonant
and the following vowel is bigger than with /ss/, and as predicted, it is found that the
perception of consonant-vowel boundary was easier than with /ss/. Although the results
differed from those of Hayes (2002), the present study also showed that the learners’
perception varied, depending on the phonetic context in which the geminate consonants
appeared.

Previous studies on single/geminate contrasts mainly used a two-altemative
forced choice task, to characterize a consonant as either singleton or geminate, so it was
perhaps assumed that if learners could not perceive a geminate consonant correctly, they
must have perceived it as a singleton, i.e., they could not perceive the correct number of
morae. However, as shown in Figures 3.8 and 3.9, many of those who could not perceive
/ss/ geminate consonants thought that they perceived a long vowel instead. This result

indicates that they at least perceived the correct duration of the relevant portion of the

62

word, i.e., having two morae instead of one. However, considering the fact that the type
of consonant does not generally affect native speakers’ perception of a geminate
consonant, one might conclude that the learners rely on a different acoustic cue from
native speakers when they perceive geminate consonants. Based on this result, at least for
some phonological conditions, it is safe to assume that, in order to correctly perceive
geminate consonants, the learners have to be able to accurately identify not only a
single/geminate minimal contrast, but also a geminate/long vowel minimal contrast.

Let us consider what acoustic cues the learners might have used to identify
geminate consonants. Figures 3.10 and 3.11 are the waveforms of /akku/ and /assu/,
recorded by a female native speaker of Japanese. The speech-waves were created with

Praat (http://www.fon.hum.uva.nl/praat/).

[a] [kl Ikul

 

 

 

 

 

 

Time (s)

Figure 3.10. Waveform of /akku/

63

[3] [8] [SH]

 

 

 

 

 

Time (s)

Figure 3.11. Waveform of /assu/l

As shown in the native speaker’s utterance, the first part of the geminate stop consonant
is silent, as shown in Figure 3.10. However, as shown in Figure 3.11, the first part of a
fricative geminate consonant is filled with frication noise, which continues into the
second part of the geminate. A possible explanation for the learners’ difficulty in
perceiving a geminate fricative consonant is this frication; the frication might have
prevented the learners from perceiving the duration of the geminate consonant correctly.
As observed in Figure 3.8 and 3.9, if a stimulus containing a geminate consonant was
misperceived as one containing a long vowel, the learners could not tell accurately which
segment the length should be attributed to; the length was incorrectly placed on the first
vowel of the stimulus so that they misperceived the fiication of the /ss/ geminate
consonant as part of the vowel length. On the other hand, some learners could allocate
length to the correct segment within the stimulus. When they correctly perceived a

geminate consonant, length was attributed to a consonant.

 

1 In the Tokyo dialect, /u/ is often devoiced between voiceless obstruents or in the word-final position,
unless the vowel is in the position to receive an accent~ However, this waveform showed that the test items
containing M were not devoiced. This may be due to the fact that the test items were read very carefully,
since the speaker was aware of being recorded for the experiment.

64

This error pattern, shown in Figure 3.8 and 3 .9, occurred most often when /u/ was
the vowel following a geminate consonant. Thus, another difficulty found in the present
study was perception of the stimuli with a low sonority vowel /u/ following a geminate
consonant, compared to a high sonority vowel /a/. Clearly, perceptibility of the vowel
affected learners’ perception of mora weight of a geminate consonant.

In perception of a fricative consonant, there might be two scenarios regarding
how the learners actually processed the stimuli containing geminate consonants: 1) they
might have taken this longer frication for the onset of the second syllable; or 2) they
might have perceived the frication noise as a coda of the first syllable. Considering the
result that the phonetic conditions influenced the difficulty of perception of geminate
consonants, principles of syllabification in English might influence which strategy was
taken. As mentioned in Ch. 3.2., English L1 speakers generally tend to follow the
Maximum Onset Principle for syllabification so that the consonants are preferred in the
onset position rather than in the coda (Goldsmith, 1990). At the same time, we have
observed that the learners’ perception was also influenced by the types of vowels
following geminate consonants. When they could perceive the following vowel clearly
but could not allocate the length correctly, the learners might have followed the principle

so that they syllabified the stimulus by the onset strategy as CV.CV, losing one mora as

shown in Figure 3.12.

65

/i\./I i Z
l i y I |
s a k a s a k a

Figure 3.12. (a) The syllabification pattern of a geminate consonant when it is perceived

correctly; (b) The pattern when a geminate is misperceived as a singleton

In such case, a mora might not be placed on the onset of the second syllable, so that the
stimulus was perceived as a singleton. This assumption conforms to Hayes (1989), which
argues that onset consonants should be non-moraic.

When they failed to hear clearly the vowel following a geminate, which was /u/
in most cases, it is assumed that they might have chosen to syllabify the consonant as a
coda since the Maximal Onset Principle did not come into play. It is assumed that in such
cases, the geminate consonant is syllabified as part of the coda of the first syllable.
Specially in cases with /ss + u/, although many learners could allocate the correct mora
weight, they failed to attribute it to the second part of the geminate consonant but
attributed it wrongly to the vowel. This is probably because relatively sonorous fiicative
consonant and fiication noise might interfere with the perception of /u/, and the second

syllable might not be clearly heard. Thus, the learners misplaced the mora weight as

shown in Figure 3.13.

66

t. I.
I/ I

Figure 3.13. Syllabification pattern of a geminate consonant when the word is

misperceived as containing a long vowel

Considering the result that /ss + u/ caused the most misperceptions, resulting in
the perception of a long vowel, this might be the scenario which most frequently occurred.
Thus, we have observed that an English syllabification strategy might be competing with
the Japanese one. Other previous studies have also reported examples in which L2
learners were influenced by Ll syllabification strategies (e.g., Derwing, 1992; Ishikawa,
2002; Schiller, Meyer & Levelt, 1997). Further research is necessary since other factors,
such as the learners’ developmental pattern or their L1 (not only English but also other
languages which have similar syllabification patterns) should be considered.

In this experiment, the question of whether the learners’ perception of geminate
consonants would be affected by some phonetic contexts and the identity of the geminate
itself was investigated, based on the hypothesis that such difficult contexts and identities
would be causes of learners’ difficulty. The result revealed that the learners had difficulty
especially in contexts with fricative geminate consonants and low sonority vowels. Hence,
their performance, as predicted, was affected by phonetic contexts and identities. In some

phonetic contexts, the learners relied on different processing cues from those used by

67

native speakers, which prevented accurate perception. The processing cues might have
been associated with the English syllabification strategy, and it seems that for those
students who misperceived geminate consonants, the processing strategy was competing
with the Japanese mora processing strategy. On processing an /ss + u/ geminate
consonant-vowel sequence, it was likely that learners were not aware of appropriate
processing cues for the processing of morae.

The next chapter will examine a proposal for effective instruction, which would
facilitate learners to identify durational contrasts, based on the assumption that the

fi'ication of a fricative consonant disrupts the perception of it as a geminate consonant.

68

CHAPTER 4

Experiment 11

4.1 Objectives of Experiment 11

As I have outlined in Chapter 2, electronic visual input is a type of computerized
input which displays the acoustic analysis of an utterance and allows learners to visualize
one or more features, such as duration, frequency range, etc. Researchers have reported
the efl’ectiveness of such training in improving learners’ perception and production (e. g.,
de Bot, 1983; Hardison, 2003, 2004; Lambacher, 1999, 2001). The research question of
Experiment 11 was to evaluate the potential benefit of instruction with visual information
to enable learners to identify a geminate consonant, based on the assumption that the
frication of a fricative consonant disrupts the perception of it as a geminate.

In Experiment I, it was found that the frication of a fiicative consonant might
prevent learners from perceiving /ss/ geminates correctly. Experiment 11 examined
whether electronic visual input that displayed this frication noise would help learners
improve their perception of geminate consonants. In addition, the stimuli were presented
in different phonetic contexts (followed by five different vowels). As reviewed in Chapter
2, in multiple trace theory, all attended perceptual details of stimuli are stored as traces in
memory (Goldinger, 1997), and a weighing scheme determines which phonetic features
to be attended to in the perception of speech signals (Jusczyk 1993). Therefore, it was
hypothesized that the visual input could successfully facilitate learners’ shift of attention
to mora weights of geminate consonants. Ifsuccessful learning occurs, the information is

stored and gathered as a composite of the traces that constitute episodic memory as

69

Hintzman (1986) and Hardison (2000) argue. Experiment I] aimed to examine whether
visual input was effective in altering the learner’s weighting scheme and preserving the
salient word length in memory. Such a process can be accounted for within the episodic

model framework.

4.2 Experimental design

The experiment consisted of the following sequence: a pretest, a lecture on using
electronic visual input, and a posttest. Two groups, an experimental group and a control
group, participated in the study. The experimental group received the instruction with
electronic visual input, while the control group received the instruction without visual
input. The pretest and posttest involved a three-alternative forced choice task in the

perception of geminate consonants in Japanese.

4.3 Method
4.3.1 Participants

The experimental group consisted of 33 learners, all native speakers of English,
who were taking a beginning Japanese course (Japanese 101) at a large university in the
US. They had received less than three months of Japanese instruction. Experiment II was
limited to beginning learners so that variables in terms of learning experience could be
controlled to some extent. The control group consisted of 31 learners, who were also
taking the same Japanese 101 course. Classes were held five times a week, for 50 minutes
each, and lectures were given that emphasized the grammatical use of linguistic

structures in Japanese, followed by practice drills. Though some general lectures on

70

"mu—=—
. A!

sounds in Japanese were given, there was no special perceptual training in durational

contrasts during the class.

4.3.2 Materials
4.3.2.1 Pretest and posttest

The stimuli consisted of 20 non-words and real Japanese words in isolation. Ten
words included fricative /ss/ geminates and singletons in five vowel environments (/a/, /i/,
/u/, /e/, and /o/). For each token, there were three choices given, which constituted
minimal triplets including a geminate consonant (e. g., /sassu/), a singleton (e. g., /sasu/)
and a long vowel (e. g, /saasu/). The basic format of the task was similar to that of
Experiment I. The participants were to identify the word they thought they heard. The
other ten words, which contained stop geminate consonants and long vowels, served as
fillers. The list of all 20 tokens was recorded by a female native speaker (the same
speaker as in Experiment I) of Japanese (Tokyo dialect) using a SONY MD MZ-RHIO-S
with a SONY ECM-CSIO microphone, at a natural rate, with accent on the first syllable.

Each token was read only once.

4.3.2.2 Instruction by electronic visual input

All the participants of the experimental group gathered and received a brief
lecture in the classroom setting between the pretest and posttest. The instructor (the
researcher, a difl’erent person from the speaker who recorded the stimuli) demonstrated
how geminate consonants appear in waveforms. The instructor’s model input of

stop/fricative geminate contrasts, such as /saklcu/ vs. /sassu/, were recorded real-time via

71

a microphone into the Praat acoustic analysis system and projected onto the screen in the
classroom, so that the participants were able to see the waveforms. The focus of this
instruction was to help learners understand the relation between the acoustic signal they
were receiving and the electronic visual representation of different types of geminate
consonants. This instruction was given for about five minutes, between the pretest and
posttest. The control group received the same lecture on the difference between stop and

fricative geminate consonants, but with no visual information.

4.3.3 Procedure

First, the pretest was conducted. The stimuli were presented separately to the
experimental and the control groups, using a SONY mini disk MZ-RHlO-S in a
classroom setting. The participants listened to each stimulus only once. After the pretest,
the instruction with visual input was given to the experimental group. The posttest was
given in the same manner as the pretest, but the order of the stimuli was randomized. The

whole procedure took about 15 minutes.

4.4 Results

The percent correct rates on perception of /ss/ geminate consonants are shown

below for both groups.

72

 

100%
90%
80%
70%
60%
50%
40%
30%
20%
10%

0%

 

—0— Experimental
+ Control

 

 

 

Mean % correct identification

 

Prete st Po sttest

 

 

 

 

Experimental Group (M, SD) Control Group (M, SD)
Pretest 67% (6.7, 1.25) 63% (6.3, 1.01)
Posttest 86% (8.6, 0.95) 69% (6.9, 1.19)
(Test items N=10)

 

 

Figure 4.1. Mean percent correct identification of /ss/ geminate consonants

There was no significant performance found between the two groups on pretest
performance; t (18) = -.726, p = .477. To see the effect of the training, a mixed design 2 x
2 AN OVA was used with group (experimental, control) as the between-subj ects variable
and time (pretest, posttest) as the within-subjects variable. The results showed that the
main effects oftime and group (F, (1, 18) = 15.918,p = 0.001, F8 (1, 18) = 7.694,p =
0.013) and the Time x Group interaction (F (1, 18) = 4.818, p = 0.042) were all
significant. Improvement over time in the perception scores differed significantly
between these two groups. The improvement for the group receiving training with visual

information was greater than that for the control group.

73

4.5 Discussion

From the result of Experiment I, I hypothesized that the learners could not
perceive a fi’icative geminate consonant correctly due to its frication. Experiment H
demonstrated a significant effect of visual information on the learners’ perception of
fiicative geminate consonants. The explanation of fricative sounds and geminate
consonants with the aid of electronic visual input was given to the learners so that they
might be able to pay special attention to fricative noise when listening to the test tokens
again. They might be able to visualize the length of words even in the absence of
waveform presentation during the task. The result of the posttest suggests that it is indeed
possible to improve learners’ perception through visual display.

Taken together, Experiments I and 11 suggest that English-speaking learners of
Japanese use a different acoustic cue from native speakers in order to identify duration.
This result is compatible with other studies done with learners whose L1 is other than
English (e. g., Min, 1987 with Korean L1 learners; Minagawa & Kiritani, 1996 with Thai,
Korean, and Chinese L1 learners). Treatment which focuses on those cues that the
learners actually use can be efi’ective in improving their perception; waveform displays of
geminate consonants helped learners to identify geminate consonants in terms of mora
attribution. It is assumed that visual information with waveform gives salience to mora
length, and shift their attention to this distinctive feature. Through training with
immediate feedback, learners add new traces which are matched against the ones already
stored in memory.

Studies by Hardison (e.g., 2003) reported that L2 speakers can be effectively

trained to perceive and produce new sounds through the auditory and visual modalities.

74

Experiment H also suggested that visual information of geminate consonants might have
succeeded in refocusing learners’ attention and altering their weighting schemes (Jusczyk
1993) by storing new traces and composing episodic memory (Hintzman 1986). These
changes were reflected in the higher score of the posttest. However, Experiment H of this
study cannot be called “training,” considering the fact that its focus was too small (only
fricative consonants) and too brief (comprising only five minutes of instruction).
Although limited, the results of Experiment II suggest that instruction with electronic
visual input can be incorporated into a more extended, effective training program.

The visual information used in Experiment H focused on frication, and it
succeeded in making the learners pay attention to the focused item. However, as shown in
the findings of Experiment I, the learners had greater difficulty in perceiving a geminate
consonant in a frame sentence, so a training program should include practice to allow
learners to become accustomed to perceiving a target phoneme in the natural flow of
conversation, not only in an identification task involving words in isolation.

In Experiments I and H, the learners’ perception of geminate consonants was
examined and the possibility of electronic visual information for instruction was
suggested. As hypothesized, the visual input could successfully facilitate learners’
attention shift to the duration of geminate consonants. The visual input succeed in making
the information stored and gathered as a composite of such traces constitute episodic
memory as Hintzman (1986) and Hardison (2000) argue.

In Experiment III, the learners’ production of geminate consonants was examined.
Experiment IV explored the potential benefits of a training program using electronic

visual information.

75

CHAPTER 5

Experiment III

5.1 Objectives of Experiment III

Experiment I examined how learners of Japanese perceive geminate consonants.
The analysis included effects of the phonetic (specifically the following vocalic)
environment of geminate consonants on the learners’ error patterns. After Experiment 1,
Experiment H was conducted to examine whether electronic visual input was effective in
mitigating the special difficulties that the learners showed in the perception data collected
in Experiment 1. Experiment 1H turned to production to see how learners of Japanese
produce geminate consonants.

As in the studies of perception, previous studies of production of geminate
consonants limited the test items to stops and did not refer to the types of geminates and
their phonetic contexts. Experiment HI investigated whether there were any phonetic
contexts and identity of geminate consonants that affect learners’ production. Thus, the
research question was to find what causes the learners’ difficulty in producing a geminate
consonant through detailed examination of such conditions.

Based on the results of these three experiments, Experiment IV was then
conducted to test a training method for learners of Japanese to perceive geminate
consonants. The training method was developed by extending the results of Experiment 11,
which examined the efl’ectiveness of electronic visual input, to a larger training program.
In addition, based on the perception and production data from Experiments I and IH, the

training was developed and studied further in order to determine whether it was

76

specifically effective in the difficult phonetic contexts.

5.2 Method
5.2.1 Participants

The participants of Experiment III were 32 college students in an elementary
Japanese course in a university in Japan. All of them were in Japan on study abroad
exchange programs from their home institutions in the US. They were all native speakers
of American English. Before coming to Japan, they had received no Japanese instruction.
At the time of data collection, the students had received Japanese instruction for about
two months at the university. The course met every day (five days a week) for 50 minutes.
The class was designed to emphasize development of oral communication skills, but was
not especially focused on sounds and pronunciation. In addition to the Japanese language
course, the students took lecture courses in their major, such as economics, culture, and
politics related to Japan. Those lecture courses were conducted in English by native
English-speaking lecturers. The students who participated in the exchange programs had
a choice of residence: they could stay with a volunteer Japanese host family or in the
student dormitory. Since the number of students who used the homestay program was
very small, the participants in Experiment IH were limited to those who stayed in a
student dormitory for the purpose of controlling the amount of Japanese to which the
participants were exposed outside of class. They spoke primarily English in the dorm,
which is understandable given that they were very beginning learners and their
roommates were also international students whose common language was English. I also

recruited five native speakers of Japanese, who were Tokyo dialect speakers and had no

77

 

sustained experience with English speakers. They served as a panel of judges who

evaluated the learners’ production.

5.2.2 Materials
Two types of production tests were used. One consisted of reading a list of words
in isolation, and the other consisted of reading a list of words in frame sentences as

shown below:

watashi wa to iimashita
1 topic that said
marker
‘1 said .’
kore wa desu
this topic is
marker
‘This is .’

The structures containing geminate consonants used for the test were identical to

those of the perception test in Experiment 1. Both tests included 12 minimal pairs of

single/geminate consonants and 6 fillers, a total of 30 Japanese real words and non-words.

The learners would not have known the real words, considering that those words had not
been taught in class and they were very early beginners. In Table 5.1, the test items are

categorized by phonetic structure.

78

at

Table 5.1

 

 

 

 

Examples of the test items

Structure of items Example V2=/u/ Example V2=/a/

(C)V1.tV2 (C)V1t.tV2 satu sattu sata satta
‘volume’ * ‘trouble’ ‘went’

(C)V1.sV2 (C)Vls.sV2 sasu sassu sasa sassa
‘stab’ ‘guess’ * ‘quickly’

(C)V1.kV2 (C)V1k.kV2 saku sakku saka sakka
‘tear’ ‘sack’ ‘refreshments’ ‘compose’

 

* indicates non-words.

5.2.3 Recording procedure

The recording of production tests was carried out individually on cassette tape
recorders in the language laboratory of the university. The participants were given a list
of words and sentences and asked to read them at a normal speaking rate. The word list

was given to the students before the recording so that they could become familiar with

the words.

5.2.4 Judgment of production

The 32 cassette tapes submitted by the participants were transformed into WAV
format. The data from all 32 participants were stored on a CD-ROM using NEC Lavie
PC-LT 700AD, and copies were given to the five native Japanese participants for the
judgment task in the language lab. They were provided a headset (Panasonic RP WH
5000-5) in a quiet room and listened to all the tokens of each learner. Their task was to
write down the words that they thought they had just heard in standard Japanese

orthography. For evaluation of sentence-level tests, the judges were given the frame

79

sentences on the evaluation sheets and asked to write in only the target words. The
stimuli for each participant were blocked in the presentation given to the judges for
ratings. The entire procedure took about 2-3 hours. At the end of the task, each judge was

offered a gift card worth 1500 yen (about US$18) for their participation.

5.3 Results
5.3.1 Results by phonetic conditions

Correctly identified items were tabulated for each item and for each subject. If a
judge correctly recognized the token the subject pronounced, 1 point was given; so if all
five judges agreed in identifying pronounce word as the correct token, a maximum score
of five was possible. For all ratings by the five judges, inter-rater reliability was
determined (using Pearson correlation) and ranged from .73 to .94.

Figure 5.1 shows comparisons between mean scores for judgment of singleton
and geminate consonants. The score for “Single” indicates the number of occasions on
which the judges perceived a singleton pronounced correctly as a singleton; the score for
“Geminate” indicates the number of occasions when a geminate consonant was

pronounced correctly and thus perceived as such by the judges.

80

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

   

 

 

 

 

 

 

 

 

5.00

4.00
0)
g 3.00 1
8 Cl Word -
g I Sentence;
0 2.00
2

1.00

0.00 ’

Single Geminate
Single (SQ) GeminateLSD)
Word level 4.35 (.26) 1.29 (.51)
Sentence level 4.23 (31) 1.62 (.64)

 

Figure 5.1. Comparison of judges’ mean scores between word level and sentence level

for single and geminate production

First, a two-factor repeated measures AN OVA was conducted. Variables were test
(word-level, sentence-level) and item (singleton, geminate consonants). Although the
effect of test was not significant, F (1, 139) = 2.611, p = .108, a significant main effect
was found for item, F (1, 139) = 488.663, p = .000, and the interaction of Test x Item was
also significant, F (1, 139) = 10.327, p = .002. As in the perception data, producing
geminate consonants was more difficult than producing singletons. Further, the mean
accuracy of producing geminate consonants was higher at the sentence level than at the
word level though the difference seems to be small, t (139) = -2.947, p = .004, while the
production of singletons was comparable in both contexts. This result was opposite to the

perception test in Experiment I, which showed a greater difficulty at the sentence level.

81

In order to examine which consonant types induced more errors in geminate
consonant production, the data for each consonant were separated and tabulated
separately as in Figure 5.2. The mean scores for the three consonant types were
analyzed with a repeated measures AN OVA, and the pairwise comparison revealed a
significant difference between /ss/ and /kk/, and between /tt/ and /kk/; F (2, 278) =
16.227, p = .000, but not between /ss/ and /tt/, (p = .471). This result is consistent with
that of the perception test, which indicated that Iss/ was the most difficult but /kk/ was

the easiest, although the difference between /ss/ and /tt/ was not significant.

 

 

2.00

 

1.60

 

 

1 .20

 

 

0.80

Mean score

 

0.40

 

 

 

 

 

0.00

 

/ss/ /tt/

 

 

 

 

/ss/ (SD) /tt/ (SD) /kk/ (SD)
Mean score 1.29 (.32) 1.35 (.46) 1.72 (.51)

Figure 5. 2. Mean production scores by consonants (n=1,576)

Further, the effect of the phonetic environment on the three consonants was

82

examined. First, the segments following the geminate consonants were also separately

examined as shown in Figure 5.3. There were two vowel conditions following the

geminate consonants: /a/ and /u/. A two-factor repeated measures ANOVA was conducted

with variables of vowel (/a/, /u/) and consonant (/s/, /t/, /k/). Both showed significant

main effects, Fv (1, 278) = 4.948, p = .028; Fe (2, 278) = 16.227, p = .000. The interaction

of Vowel x Consonant was also significant, F (2, 278) = 12.481, p = .000. When /u/ was

the following vowel (1.52), fewer errors were produced than with /a/ (1.38).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2
1.5
i
g 1 I /+a/
5 Cl /+u/
I)
2
0.5
O l 1
/ss/ /kk/
/ss/ (SD) /tt/ (SD) /kk/ (SD)
/-l-a/ 1.39 (.34) 1.18 (.32) 1.59 (.76)
/+u/ 1.19 (.32) 1.5 (.43) 1.86 (.46)

 

Figure 5. 3. Mean production scores by vowels following geminate consonants

Among consonants, pairwise comparison showed significant results; when the following

vowel was /u/, the difficulty hierarchy was the same as that shown by the perception test

83

result; the /ss/ fiicative consonant was the most difficult among the three, and the /kk/
stop consonant was the easiest. However, when the following vowel was /a/, the /tt/ + /a/
combination was the most difficult among the three consonants, and there was no
significant difference between /ss/ + /a/ and lkk/ + /a/.

Next, Figure 5.4 showes a comparison made between the two difl’erent preceding
segments: /sa/ and /a/. A two-factor repeated measures AN OVA was conducted. Variables
were preceding segment(s) (/sa/, /a/) and consonant (/s/, It], fk/). Both showed significant
main effects, Fp, (1, 278) = 8.035,p = .005; F6 (2, 278) = 16.227,p = .000. The

interaction of Preceding Segment x Consonant was also significant, F (2, 27 8) = 14.245,

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

p = .000.
2
1.5
E
o
8 1 I /sa+/
5 1:1 /a+/
0
E
0.5
0 l 1
/ss/ /kk/
/ss/ (SD) /tt/ (SD) /kk/ (SD)
/sa+/ 1.37 (.35) 1.01 (.59) 1.65 (.46)
/a+/ 1.21 (.31) 1.62 (.35) 1.79 (.79)

 

Figure 5. 4. Mean production scores by preceding segment types

84

The mean scores for the environment with consonant /S/ + vowel /a/ as preceding
segments (1.34) were significantly lower than those with only the vowel /a/ (1.54).
However, pairwise comparison showed that only for /tt/ geminate consonants was the
difference between /sa/ and /a/ significant; there was no difference between /sa/ and /a/
with relation to the other two consonants. The cause of these results in production might
be the judges’, that is, the native Japanese speakers’, perspective. Previous studies agree
that the length of preceding vowels will affect native Speakers’ perception of a geminate
consonant (Toda, 1998); if the duration of the preceding vowel is longer, the perceptual
boundary dividing a geminate consonant and a singleton will become bigger; in other
words, native speakers would tend to perceive the token as a geminate consonant; this
difference is applicable to either fricative or stop consonants. In the present experiment,
the learners’ pronunciation of the fricative /S/ of /sa/ might be perceived as part of the
duration of the following segment, making not just long vowels but sequences of
continuant consonants plus short vowels another salient feature producing the NS

perception of gemination.

5.3.2 Error patterns
The perception test in Experiment I revealed that many learners inaccurately
perceived geminate consonants as long vowels. For comparison, the error patterns in the

production of geminate consonants (/CC+u/) were also examined, as Shown in Figure 5.5.

85

 

100%
90%
80%
70%
60%
50%
40%
30%
20%
10%

0%

Cl Long Vowel
I (Geminate)
Singleton

 

 

Answer ratio

 

/ss/ /tt/ /kk/

 

 

 

Figure 5. 5. Ratio of errors: Production of geminate consonants (/CC+u/)

The misproduction of singletons as geminate consonants did not occur as
frequently as in the perception test in Experiment I (Figure 3.9). Misproducing a
geminate consonant as a long vowel was limited throughout the three consonant types,

and there were no differences among them.

5.4 Discussion

In Experiment IH, learners’ production of geminate consonants was studied by
having them read the test words in isolation and in frame sentences. The learners showed
greater difficulty in producing geminate consonants than singletons. The majority of
errors were made by misproducing a geminate as a singleton.

Producing geminate consonants at sentence-level showed higher correct score
than producing them at word-level. The previous studies of L2 production of long vowels

(Koguma, 2001) and geminate consonants (Hirata, 1990b) in Japanese demonstrated a

86

greater accuracy at word level, and the researchers suggested that this was because less
attention might have been paid to the target tokens (e.g., long vowels, geminate
consonants) in sentence-level production since the other elements in the sentences would
have distracted the learners’ focus. There are a number of other studies suggesting a
significant correlation between learners’ accuracy and attention in L2 acquisition (e. g.,
Dickerson & Dickerson, 1977; Lin, 2001; Sato, 1984; Schmidt, 1987; Tarone, 1982). One
important difference between the current work and previous studies (e. g., Koguma, 2001;
Hirata, 1990b) is the proficiency level of the participants. While the participants of these
previous studies had experienced learning Japanese for some time, the participants of the
present experiment were at the very beginning level. For such learners, reading sentences
might have required much more attention, and reading words might have been much
easier, requiring less attention, which might have been the cause of the higher accuracy
level in sentence-level production in my data. It is assumed that learners’ proficiency
level might afl’ect the direction of learners’ attention in a reading task. On the other hand,
the perception data in Experiment I showed an opposite tendency; sentence-level
perception of geminate consonants were more difficult. Directing attention to items in
larger contexts in perception might be more difficult than in production at the beginning
level. Further research will be necessary to fully explain these results.

Comparison among the three consonant types revealed that producing /kk/
geminate consonants was Significantly easier than producing the other two consonants,
/ss/ and /tt/. lss/ geminate consonants were the easiest, although there was no significant
difference between /ss/ and /tt/. It seems that the result is comparable with the perception

data to some extent, although any comparison of the perception and production data

87

should be made with caution because of the different subject groups.

Detailed examination showed that the phonetic environment affected learners’
production. As in the perception experiment, /a/ and /u/ were chosen as the vowels
following the geminates. Comparison between these two conditions revealed that the
production of geminates + /u/ was easier than geminates + /a/. As noted in the previous
chapters, the cause of difficulty in perceiving a geminate consonant + /u/ could be due to
the lower sonority of the vowel, but such a sonority difference did not appear to affect the
learners’ production, at least not in the same way. This result adds to the literature
demonstrating that perception does not necessarily parallel production in L2 phonological
learning. With regard to consonant type, the /tt/ + /a/ combination was significantly more
difficult than the other two consonants in production, and there was no difl’erence
between /ss/+/a/ and /kk/+/a/. This, of course, suggests an interaction between consonant
and vowel identity and will require fiirther study.

An analysis of the types of error patterns was also made. In the perception data
of Experiment I, misperception of the stimuli including a geminate consonant as
including long vowels was found most frequently in the /ss/ + /u/ stimuli. This result
indicated that the learners could allocate the correct mora weight but had troubles with
attribution of length in the stimuli. However, production data showed no such tendency
for any of the three consonant types. The most frequent error pattern was misproducing
the stimuli with geminate consonants as having singletons, so the learners had trouble
with allocation of the length itself. The misperception of words with /55/ geminates as
having long vowels indicated that the learners were sensitive to mora weight. Since the

production data did not indicate such a tendency, the influence of durational contrasts on

88

production seems to be a more difficult issue and will require fiirther study. In Broselow
and Park (1995), Korean learners at a certain stage of proficiency showed a tendency for
mora conservation, which is a resistance to the loss of morae, by inserting an extra vowel
in production. The production data in Experiment HI showed that the learners had
perhaps not reached that stage yet, while the learners in the perception study in
Experiment I showed a tendency for mora conservation although they had troubles with

the attribution of the mora.

89

CHAPTER 6

Experiment IV

6.1 Objectives of Experiment IV

Based on the results of Experiments I-III, Experiment IV was then conducted to
test a training method to improve the ability of learners of Japanese to perceive geminate
consonants. The training method was developed by extending the results of Experiment H,
which examined the effectiveness of electronic visual input as part of a larger training
program. In addition, based on the perception and production data from Experiments I
and HI, the training was developed in such a way as to permit investigation into whether
it was specifically effective in the difficult phonetic contexts.

The main research question of Experiment IV was to the effectiveness of training
using electronic visual input in the perception of geminate consonants; the effectiveness
was assessed through a comparison of auditory-visual (AV) and auditory-only (A-only)
training. The visual materials involved the speechwave displays of the stimuli created by
Praat, which is the software that creates visualizations of speech signals and that was
used in Experiment H. In addition, by conducting a production test as well as a perception
test, the relationship between perception and production was also examined.

Previous studies demonstrated that perceptual training with visual input was
effective for L2 learners (e. g., Hardison, 2004, 2005a), therefore, it was hypothesized that
the training with speechwave displays as visual information would also be effective to
train J apanesZ L2 learners. As reviewed in Chapter 2, to establish new L2 perceptual

categories, learners must develop a new attentional weighting scheme for optimal

90

processing of the distinctive features of the L2 Speech input. Experiment H demonstrated
that the use of speech waveforms of geminate consonants as visual input might be
effective for the development of such processing. In multiple-trace theory, all attended
perceptual details of stimuli are stored as traces in memory (Hintzman, 1986). The
information stored and gathered as a composite of such traces constitute episodic memory
(Goldinger, 1997; Hardison, 2000, 2003; Hintzman, 1986). Training with visual input
could direct learners’ attention to the salient timing features (mora lengths) to be
preserved in memory. Thus, another objective of Experiment IV was to account for the
result of the AV training within the episodic model framework.

The experiment was carried out in a pretest-posttest design. The posttest was
followed by a generalization test to examine whether the result of the training could be
transferred to novel stimuli. Following the generalization test, a follow-up interview was
conducted to collect qualitative data on the effectiveness and efficiency of the training
from the learners’ perspective. They were asked questions such as whether perceiving the
difl’erence between a singleton and a geminate consonant had been difficult before the
training, and how difficult it became after the training; what they thought caused such
difficulties in perception; whether they had any special strategy to identify a geminate
consonant; whether there were any items that were particularly difficult to perceive; and
whether they thought the training was effective. They were also asked to comment on the

web-delivered training format.

91

6.2 Method

6.2.1 Participants

A total of 30 students were recruited from among the participants in Experiment
III, the purpose of which was to examine their production of geminate consonants (two
students from Experiment 111 did not participate). Those 30 participants were divided into
two groups based on the results of the perception pretest, which will be explained later,
so that the average test scores of both groups were comparable prior to training. In
addition, 10 students participated in the study as a control group; they took only the
pretest and posttest, but received no training.

The AV group received auditory and visual (electronic visual input) training and
consisted of 15 students. The other 15 students formed the A—only training group, which
received similar training (i.e., the same oral instructions and auditory input) but were not

presented with visual information.

6.2.2 Pretest
6.2.2.1 Production test

The data from Experiment [H were used as the pre—training production data.

6.2.2.2 Perception test

Before the training sessions started, the participants gathered and took a
perception test in a classroom setting, which was the same perception test as was used in
Experiment I. As explained below, the same stimuli, recording materials, and test

procedures were used.

92

6.2.2.2.1 Materials

The recorded material was the same as in Experiment I. The stimuli were
recorded by a female native speaker of Japanese (Tokyo dialect) using a SONY MD
MZ-RHIO-S with a microphone SONY ECM-CSIO. Two tests were conducted: Test 1,

the words in isolation; and Test 2, words in the frame sentences that follows:

 

watashi wa to iimashita
I topic that said

marker

‘1 said .’

kore wa desu

this topic is
marker

‘This is .’

In each test (word-level, sentence-level), stimuli consisted of 30 bisyllabic Japanese real
words and non-words, which included 12 singletons, /(C)V.CV/, and 12 geminate
counterparts, /(C)V.C.CV/, where the first (C)V and the final CV were identical between
each word in a minimal geminate-singleton pair, and 6 fillers which were bisyllabic
words consisting of three morae, but including no geminate consonant. The types of test
items are as follows:

Target geminate consonants: /Ss/, /tt/, /kk/

The segments preceding the target consonant: /sa/, /a/

The segments following the target consonants: /a/, /u/

Table 6.1 Shows some examples:

93

Table 6.1

Examples of the test items

 

 

 

 

 

Example
Structure of items V2=[u] V2=[a]
(C)V1.tV2 vs. (C)Vltth satu vs. sattu sata vs. satta
(C)V1.sV2 vs. (C)VlssVz sasu vs. sassu sasa vs. sassa
(C)V1.kV2 vs. (C)Vlkkvz saku vs. sakku saka vs. sakka

 

The same set of 30 words was used for both tests, but the order of presentation was

randomized. The maximum score for each test is 24, so the total score is 48.

6.2.2.2.2 Procedure

The stimuli were presented in a classroom setting on the same MD player as the
one used for recording. A three-alternative forced choice identification task was used for
the word-level and the sentence level tests. The learners were instructed to choose from
one of three options given, which consisted of minimal triplets including a singleton
consonant /(C)V.CV/, a geminate consonant /(C)V.C.CV/, and a long vowel /(C) V.V.CV/,

where the first and final CV were identical between the members.

6.2.3 Perception training
6.2.3.1 ”Raining materials

The basic structures of words and sentences used for the training followed the test
materials. Although the stimuli of the perception test in Experiment I included only

minimal pairs for Singleton and geminate consonants, considering the result which

94

 

showed that many students inaccurately perceived geminate consonants as long vowels, it
also appeared to be necessary for learners to be able to distinguish long vowels from
geminate consonants. Therefore, the training words were divided into three categories,
forming minimal triplets of bisyllabic words: (1) words containing singleton consonants,
(2) words containing geminate consonants, and (3) words containing long vowels. The

tokens were either in isolation or in such sentence frames as the following:

watashi wa to iimashita l
I t0pic that said
marker
‘1 said .’
kore wa __ desu
this topic is
marker
‘This is .’

As a form of training, web-delivered material was selected. Compared to
laboratory training sessions, which have been traditionally used for L2 perception
training, on-line training material is easier for learners to access, and it allows them to
learn at their own pace. The on-line format might also reduce the learner’s anxiety or
stress. As described above, the learners were instructed to take 10 sessions for about
15-20 minutes each, but it was left to the learners to decide what time in the day and
where to take the training. Thus, easy access and a less stressful environment are some of
the advantages of web-delivered training. However, in exchange for such flexibility, there
is a drawback for research purposes; without the presence of an observer, there is no way

to watch and control the amount and frequency of training learners really take.

95

The training material was created by transforming the speechwave displays
created by the Praat data by using Macromedia Flash MX 2004. Flash is a multimedia
authoring program, which enables a user to create animation with sound in a very simple
way. The stimuli created by Praat were converted to SWF files when saved in Flash.
Using the SWF file, on the webpage, learners could listen to the sound and

simultaneously view the waveform and the movement of the cursor through the

waveform (see Figure 6.1).

 

3”” "W ' , x ., ”47 .....
Fin see em Fm reek rise

was”. we ~ 3;] GI amiss 317m 314m 4 3"; J@ ...-.-J , _

‘ W11}; Hip/Mm Wn'mmi hm _ j; {969‘ “in;

 

 

 

 

 

Please click ’ below, then answer the question.

0 03644

 

 

 

 

 

 

 

 

07397
fl 1. I 7552
Time (s)

 

 

 

Figure 6.1. Waveform display

96

For the A-only group, this waveform display was not given; only the auditory stimuli
were played. Below the waveform display, in a dialogue box that learners opened by
moving the curser down, the learners were asked to identify the word they heard from
three alternatives that appeared on the computer screen as in Figure 6.2. Such multiple

choice exercises can be easily created using free downloadable e-learning tools which

are abundant now on the web.2

 

 

 

 

 

 

D710
5 Time (a)

"‘"' Clickthe word that you heard:

C sattsu

 

C aatsu

C gtsu

Please click the "Check" box to check your answer.

 

 

 

 

Figure 6. 2. Exercise questions display

 

2 The present study used “Web Quiz Creating Tool” provided at http://www.fi1reai.or.jp/~irie/webquiz

97

Immediately after responding by clicking an answer on the screen, they received
feedback; if they chose an incorrect answer, “Wrong!” appeared, and they had a second

trial. If they answered correctly, the screen showed “Correct!” as in Figure 6.3.

.1

 

 

 

I": "

 

 

Figure 6. 3. Feedback display

Either a word-level token or sentence-level token appeared randomly. The
selection of the words and sentences were changed every day, while all types of stimuli

were presented equally every day.

6.2.3.2 Th'aining procedure

As described above, based on the result of the perception pretest, the 30 learners
were divided into two groups: the AV group and A-only group. Before the training began,
the two groups met separately for an instruction session about the experiment. To the
AV-group, a lecture about geminate consonants and a demonstration of Speech waveforms
was given for about five minutes, similar to the one given in Experiment H, so that the
learners could see how differently some acoustic features of geminates and singletons
were realized graphically. The A-only group also received the same lecture about
geminates, without the waveform demonstration. In this instruction session, a trial

web-session was also given in order to teach the learners how to access the materials,

98

which they would have to do on their own, and in order to observe how many minutes it
would take the learners to go through a training session.

The appropriate amount of training depends on the type of training used. In Logan,
Lively, and Pisoni (1991), about 280 stimuli were presented to participants. Each session
lasted 40 minutes, and a total of 15 sessions were undergone. This type of training
represented relatively implicit learning, and that type of learning generally requires more
training stimuli and sessions than training involving explicit instruction about the target.
While Logan et al. (1991) and Yamada et al. (1995) conducted 8 sessions and 15 sessions,
respectively, the present study provided 10 training sessions; this number chosen
considering the explicit nature of the instruction. The amount of time for each session
was about 15-20 minutes. This approximate time was averaged from among all the
learners observed in the trial sessions. The participants were instructed to take 10 sessions,
one session per day for two weeks, by the deadline date.

The learners began each session by accessing the researcher’s website, where the
training program was uploaded. They clicked the “start” button, and the stimuli played.
For the AV group’s training session, the sound (e. g, ‘attsu’) and visual (e. g., the
waveform of ‘attsu’) stimuli appeared on the display as shown in Figure 6.1. They were
also instructed to report any problems with the training session, and also to make a
report if it took them too short a time (less than 10 minutes) or too long a time (more
than 15 minutes) to complete the training session; however, no such report was brought

throughout the training period.

99

6.2.4 Posttest
6.2.4.1 Perception test and production test

After all 10 perception training sessions, the learners gathered and took a posttest
in a classroom setting. The test materials included the same set of stimuli as the pretest.
In order to see the effect of perception training on production improvement, a production

test was given before the perception test, in the same procedure as the pretest.

6.2.4.2 Generalization test

In order to examine whether the effect of training could be transferred to
unfamiliar tokens pronounced by a different speaker, a generalization test in perception
was also conducted, immediately following the posttest. The test consisted of words
containing singletons, geminate consonants, and long vowels; the latter had not been
included in the training stimuli. A new talker, who was also a female native Speaker of the
Tokyo dialect of Japanese, recorded the stimuli. A three-alternative forced choice task
was used as in Experiment I. In addition to /u/ and /a/, /i/, /e/, and /o/, i.e., all the Japanese
vowels were included following the consonants to examine whether effects of the training
had been transferred to the untrained vowel contexts as well. These vowels can occur
following any type of consonant. The stop consonant /p/ was also included, and long
vowels were added to the Singleton and geminate counterparts. A total of 24 tokens (12
tokens x 2 levels [word-level and sentence-level]) and six distracters were presented.
Examples of words with geminate consonants are presented in Table 6.2. Singletons and
long vowels with identical combinations of consonants and vowels were also included in

the test as distracters.

100

Table 6.2

Examples of the geminate consonants

 

 

 

 

 

 

Vowel type
consonant /a/ /i/ /u/ /e/ /o/
/s/ - /sassi/ - /sasse/ lsasso/
/p/ /Sappa/ /Sappi/ /sappu/ /sappe/ /Sappo/
/t/ - /Satti/ - /satte/ lsatto/
/k/ - /sakki/ - /sakke/ /sakko/

 

6.2.4.3 Follow-up interview

To obtain insight into the training approach from the learners’ point of view, a
follow-up interview was conducted with each of the learners. The interview was carried
out individually in the researcher’s office for about ten minutes. The learners were asked
questions such as whether they found it difficult to identify geminate consonants; what
they thought the causes of such difficulty were; and how the difficulty changed after the
training. They were also asked for overall comments on the training sessions: how they
found the training; what effects they thought it brought; and when they used the training

during a day.

6.3 Results

The mean percent of correct answers for pretest and posttest was tabulated. The
results are discussed in the following order: a) comparison of training types (AV, A-only,
Control), b) a comparison of posttest and generalization tests between the training groups

(AV, A-only), c) a comparison of word-level and sentence-level test between AV and

101

 

A-only groups, (1) the effect of consonant types and the following vowels in the
word-level test (AV group), e) the effect of consonant types and the following vowels in
the sentence-level tests (AV group), and f) the error pattern of the AV group by consonant
type. Finally, production test results (per group, and by consonant type), and a
comparison of individual results within the AV group (perception and production in

pretest and posttest) are presented.

6.3.1 Comparison of training types (AV, A-only, Control)

In order to examine the effects of training, both group (AV-group and A—only
group) and time (pretest and posttest) were considered, as shown in Figure 6.4. A
one-factor ANOVA indicated that the mean percent correct identification scores before
training among the AV-group (59%), the A-only group (56%), and the Control group
(54%) were comparable, F (2, 53 8) = .612, p = .552. Though the scores for both training
groups showed an increase in the posttest, the score of the AV-group (86%) was higher
than that of the A-only group (66%). A mixed design 2 x 3 AN OVA was used with time
(pretest, posttest) as the within-subj ect variable and group (AV, A, Control) as the
between-subject variable. The results showed significant main effects of time and group,
F,(1, 538)=135.985,p = .000, Fg (2, 538) = 8.211,p = .000. The Time x Group
interaction was also significant, F (2, 538) = 847.750, p = .000. The post-hoc test
(Tukey’s HSD) revealed that gains were significantly greater for the AV-group compared

to the A-only and Control groups; the latter two groups showed no significant difference.

102

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

100
C
O
"3 80 /‘
u?
'5
c /
.5. 50 —e— AV
‘g —I— A-only
5 40 + Control
0
BB
5 20
C)
2

0 l
Pretest Posttest
Pretest (ll/I, SD) Posttest (M, SD)

AV 59% (14.26, 4.44) 86% (21, 2.49)

A-only 56% (13.44, 3.82) 66% (16, 3.21)

Control 54% (13, 3.74) 59% @413, 3.36)

 

(Test items N=24)

Figure 6. 4. Mean percent correct identification for perception pretest and posttest

Thus, the greatest improvement was observed for the AV training group. This result is
consistent with Hardison (2003 ), which compared AV-training and A-only training. In
Hardison’s study, talker’s face with visible articulatory gesture was used as a visual cue to
train Japanese and Korean learners to identify /r/ and /l/. The result showed a significant

advantage for AV-training.

6.3.2 Results of generalization test
Next, the results of the generalization test were analyzed. This test included 24
tokens (12 tokens x 2 levels) involving the untrained geminate consonant /p/, and the

bisyllabic words containing long vowels. Figure 6.5 shows the effectiveness of the

103

 

training on the students’ ability to correctly apply the training to novel tokens.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

100%
,8 .—
§ 80% T.
I;
'33
i: I\
3': 60% \-
'5 + AV
0 —I— A- l
E 40% on y
o
8
5 20%
0
2

0% ‘
Posttest Generalization
Posttest (M, SD) Generalization(M, SD)
AV-Group 86% (21, 2.49) 83% (19.80, 2.96)
A-only Group 66% (16, 3.21) 55% (13.3, 3.22)

 

(Test items N=24)

Figure 6. 5. Mean percent correct identification for posttest and generalization test

A mixed design 2 x 2 ANOVA was conducted. Variables were group (AV, A-only) and test
(posttest, generalization test). Both had significant main effects, Fg (1, 358) = 13.377, p

= .000; F, (1, 358) = 82.071, p = .000. The interaction of Group x Test was also
significant, F (1, 358) = 13.385, p = .000. The decrease in accuracy between the two tests
was greater for the A-only group. This result indicated that the effect of AV training could

be transferred to unfamiliar tokens and a new voice.

6.3.3 Results of the AV-group
6.3.3.1 Word level vs. Sentence level

Since the interest for the present study is in examining the effect of AV training in

104

7‘1

detail, further analyses were conducted on the results of the AV-group. First, we have
already observed that there was a significant improvement from the pretest to the posttest,
but the result was firrther analyzed at the two different levels of the test, word vs.
sentence, shown as in Figure 6.6. Recall that the results of Experiment I showed that the
learners found geminates more difficult to identify at the sentence versus word level.
Therefore, it was considered important to see whether there was any difference in

improvement between these two levels after training.

1777—3. T '
I ='

 

 

111196

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C
O
.5
8
SE
‘5' 60%
§ I/ +Word
.._. —I— Sentence
8 40%
is
2.2 20%
5
3 0% '
Pretest Posttest

Pretest Posttest Gains
Word level 66% 8 1% 1 5%
Sentence level 53% 92% 39%

 

Figure 6. 6. Mean percent correct identification in pretest and posttest for word-level and

sentence-level geminate consonants

First, comparison was made between word-level and sentence—level perception in the

pretest. The result showed that sentence-level (53%) was significantly more difficult than

105

word-level (66%); df= 11, t= 2.277, p = .044.

Next, a two-factor repeated measures AN OVA was conducted on the AV group
data. Variables were time (pretest, posttest) and test (word level, sentence level). The
effect of test was not significant, but there was a significant main efl’ect of time, F (1, 14)
= 17.742, p = 0.001, and the interaction of Time x Test was also significant, F (1, 14) =
14.253, p = 0.002. The interaction indicated improvement over time differed significantly

between word-level and sentence-level perception. As Figure 6.6 indicates, the gain in

 

scores as a result of the training differs in that the sentence-level test Showed gains of
more than twice those of the test using word-level stimuli. The effectiveness of
AV-training is more pronounced in sentence-level perception, which the learners found

more difficult in the pretest.

6.3.3.2 Word-level perception

Further analysis focused on the word-level and sentence-level data from the AV
group. Figure 6.7 shows the data of word-level perception. A comparison was made using
the identification accuracy scores in the pretest and posttest for the three different

consonants, /s/, /t/, and /k/, with the two difl’erent post-consonantal vowels, /a/ and /u/.

106

 

 

 

 

 

Mean % Correct Identification

 

 

 

 

 

 

 

 

s t k
/s/ /t/ /k/
/u/ /a/ /u/ /a/ /u/ /a/
Pretest 37% 60% 70% 73% 73% 77%
Posttest 70% 87% 75% 93% 90% 93%

 

Figure 6. 7. Mean percent correct identification for each consonant (/s/, /t/, /k/) and each
post-consonantal vowel (/a/, /u/) in pretest and posttest for word-level geminate

consonants

To assess the effects of training, a three-factor repeated measures ANOVA was conducted.
The variables were time (pretest, posttest), consonant (/s/, /t/, /k/), and vowel (/a/, /u/). All
had significant main effects, F, (1, 29) = 41.308,p = .000; F0 (2, 58) = 22.929,p = .000
and F v (1, 29) = 33.305, p = .000. The means for /s/ was significantly lower than that for
the other two consonants, while there was no significant difference between /t/ and /k/.
Although Time x Vowel interaction was not significant, the Time x Consonant

interaction was significant, F (2, 58) = 10.119, p = .000, indicating the increase in scores

107

varied significantly by consonant. In addition to the interaction between Consonant and
Vowel, F (2, 58) = 18.125, p = .000, the Time x Consonant x Vowel interaction was
significant, F , (2, 58) = 5.23 6, p = .008. The improvement of /t/ and /k/ was almost
parallel, though overall performance of /k/ was better. The scores for /s/ were the lowest
in both the pretest and the posttest (48% and 79%, respectively), however, /s/ Showed the
greatest improvement. Further, although /s/ + /u/ showed the lowest mean accuracy in the
pretest, and was found the most difiicult combination in Experiment I, it showed the

greatest improvement — a percentage rise of 34%.

6.3.3.3 Sentence-level perception

Separate analyses were conducted on the sentence-level data. Figure 6.8 shows

the sentence-level perception accuracy.

108

 

 

‘ Elp'etest—/u/
. Ineteslr/a/
Dposttesb/u/
..c - - /a/

Mean % Correct Identification

 

 

 

 

 

 

 

 

/s/ /t/ /ld
/u/ /a/ /u/ /a/ /u/ /a/
Pretest 3 3% 53% 50% 60% 63% 63%
Posttest 96% 93% 90% 93% 87% 90%

 

Figure 6. 8. Mean percent correct identification for each consonant (/s/, /t/, /k/) and each

post-consonantal vowel (/a/, /u/) in pretest and posttest for sentence-level geminate

consonants.

A three-factor repeated-measures AN OVA was conducted on the results of the

sentence-level test, with time (pretest, posttest), consonant (/s/, /t/, /k/), and vowel (/a/,

/u/) as variables. Again, all variables had significant main effects, F, (1, 29) = 65.862, p

= .000; F, (2, 58) = 5.342,p = .007 and F, (l, 29) = 20.714,p = .000. There was also no

significant difference in the means between /t/ and /k/, while that for /s/ was significantly

lower than the other two consonants.

A significant Time x Consonant interaction was found, F (2, 58) = 45.877, p

109

= .000, again indicating the increase in scores varied significantly by consonant. The
pretest score indicated /s/ was the lower (43%) than /t/ (5 5%) and /k/ (63%); however, the
posttest score for /s/ (95%) exceeded the other two, /t/ (92%) and /k/ (89%). A significant
Time x Vowel interaction was also observed, F (1, 29) = 7.864, p = .009; in the pretest,
the score for /a/ (59%) exceeded that for /u/ (49%), however, in the posttest the score for
/u/ (91%) was almost tied with that of /a/ (92%). Although the Consonant x Vowel
interaction was not significant, a significant Time x Consonant x Vowel interaction was
observed. The improvement in the perception of geminate consonants with /S/ + /u/
combination was the largest; in the pretest, the score was the lowest among the three
consonants (33%), but at posttest, it was the highest (96%). The effect of the training at
the sentence level was most evident for /s/ + /u/, which was the most difficult
consonant-vowel sequence in Experiment 1. Taken together with the results at word level,
these findings suggest that the AV-training contributed the most to improve perception of
the most difficult condition for the learners. This result is consistent with previous
training study (Hardison, 2003). In Hardison’s study on Korean and Japanese learners of
English, visual input contributed the most to the perception of the /r/-/l/ contrast sounds
in the more difficult environments, which are utterance-initial for the Japanese subjects
and syllable-final for the Koreans. These difficulties were based on pretest identification
accuracy and were predicted by their L1 phonology. Considering the observation in
6.3.3.1, which Showed that the sentence-level accuracy in the posttest exceeded the
word-level accuracy, it is also suggested by the present study that perceptual training with

visual information was particularly effective in difficult environments.

110

.___, ____'

6.3.4 Error pattern (AV group)
In Experiment I, it was found that the learners tended to perceive words
containing a geminate consonant as containing a long vowel, and this tendency was
especially strong in the perception of the fricative geminate consonant /s/. To assess the
effect of the training in reducing such errors, the error rate of inaccurate perceptions of
words containing geminate consonants as containing long vowels was analyzed with an N,
AN OVA. The variables were time and consonant. Main effects were found for both time, .
F (1, 119) =28.876,p = .000, and consonant, F(2, 238) = 9.318,p = .000, and the
interaction of Time x Consonant was also significant, F (2,23 8) = 21.591, p = .000.
Tukey’s HSD reveals that in the pretest, the error rate of /s/ was significantly higher than
that for /t/ and /k/ while these latter two were not statistically different. However, in the
posttest, all three consonants showed no significant difference. The result of comparison

is Shown in Figure 6.9.

111

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

30%
25% \
§ \
El 20%
g \ + S
§ 15% —l— t
'g \ + k
as 10%
§ \
2 5% \.
0% i
pretest posttest
/s/ /t/ /k/
pretest 28% 15% 14%
posttest 3% 5% 7%

 

Figure 6. 9. Mean percent misperception of geminate consonants as long vowels for each

consonant type in pretest and posttest

As Experiment I and the pretest of Experiment IV indicated, the fricative geminate
consonant was perceived less correctly than the other two stop geminate consonants, but
the fricative geminate consonant showed the highest improvement rate of the three. In
sum, the training contributed the most to improvement in the perception of /s/ geminate

consonants.

6.3.5 Production test
Experiment IV also aimed to examine whether production would be improved as
a result of perceptual training. The Japanese judges’ pretest and posttest scores were

totaled, and the means were calculated for each learner in the training groups and the

112

control group.

6.3.5.1 Judgment of production

The contents of the cassette tapes submitted by the learners were transformed
into WAV format. The data fi'om all 40 learners were stored on a CD-ROM, and copies
were given to the five native Japanese raters for the judgment task in the language lab.
They were provided with a headset in a quiet room and listened to all tokens produced by
each learner. Their task was to write down the words they thought they had just heard
using standard Japanese orthography. The stimuli provided to the learners were blocked

from the presentation to the judges for their ratings.

6.3.5.2 Results

Correctly identified items were tabulated for each item and for each subject. If a
judge correctly recognized the token the subject pronounced, 1 point was given; therefore,
if all five judges made correct judgments of the token, a maximum score of five was
possible. For all ratings by the five judges, inter-rater reliability was determined (using
Pearson correlation) and ranged from .72 to .96 by category of token (consonant /s/, /t/,
/k/; pre-consonantal segment lsa/ and /a/; post-consonantal vowel /u/, /a/). The highest
coefficient was found in judgment of /a/ + [kk/ + /a/, while the lowest was /sa/ +/tt/ + /u/,
which was also found to be relatively difficult to perceive in the production data of
Experiment IH.

Figure 6.10 shows the result of the production tests of the three groups.

113

 

 

 

3.5

2.5 /
2 //l + AV

—I— A-only
1.5 —A + Control

 

 

 

 

 

 

 

 

Mean score

 

 

 

 

 

 

 

 

 

 

 

 

0.5
I 0 1
' Pretest Posttest
Pretest (SD) Posttest (SD)
AV Group 1.59 (1.04) 3.14 (.70)
A-only Group 1.46 (.72) 2.38 (.68)
Control 1.39 (.61) 1.45 (.49)

 

Figure 6.10. Mean ratings for the production test

A mixed design 2 x 3 ANOVA was conducted with time (pretest, posttest) as the
within-subject variable, and with group (AV, A-only, Control) as the between-subject
variable. The results showed significant main effects of time and group, F, (1, 219) =
21 .473,p = .000; Fg (2, 219) = 18.974, p = .000; and a significant Time x Group
interaction, F (2, 219) = 8.837, p = .000. Tukey’s HSD revealed that scores for the three
groups, as shown in Figure 6.10, were significantly different. While the mean scores
before training between the AV-group (1.69), A-only group (1.46), and Control group
(1.39) were comparable, which was statistically confirmed by a one-factor ANOVA, F (2,
219) = 1.921, p = .149, the perceptual training improved production for the AV and

A-only groups to a significantly different degree. The mean posttest score for the A-only

114

 

training group (2.38) was significantly lower than that for the AV group (3.14). Again, AV
training contributed to greater improvement.

Further analysis of the AV—group data was done to examine how production of
each consonant type was improved. For analysis, a repeated-measures ANOVA was used.
The variables were time and consonant. The main effects of these two variables, F, (l,
74) = 151.038, p = .000, F, (2, 148) = 26.342, p = .000, and the interaction of Time x
Consonant, F (2, 148) = 3.757, p = 0.026 were significant. Improvement over time in the
production scores differed significantly according to the consonant as shown in Figure

6.11.

 

4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00

 

 

 

Mean score

 

 

pretest posttest

 

 

 

 

/Ss/ (SD) /tt/ (SD) /kk/ (SD)
pretest 1.36 (1.24) 1.44 (1.13) 1.76 (.98)
posttest 3.34 (.74) 3.08 (.57) 3.82 (.81)

gain 1.98 1.64 2.06

Figure 6.11. Mean production rating for each consonant type in pretest and posttest for

the AV training group.

115

 

Although the three consonant types showed significant improvement in the
posttest, Tukey’s HSD showed that improvement of /tt/ geminate consonants was
significantly lower, while /kk/ was the highest. /ss/ was significantly lower than /kk/, but
the actual gain of /ss/ (1.98) was close to that of /kk/ (2.06). As we have seen, the greatest
perception improvement was also found for /ss/. This result suggests a close link between

perception and production.

6.3.6 Individual development for the AV training group
Tables 6.3 and 6.4 Show individual development in perception and production
respectively, by comparing percentages between pretest and posttest scores. The
improvement rate was obtained by dividing the difference between the pretest score and
the posttest score by the pretest score.
In the perception data, the learners whose score was higher than average (62%) in
the pretest showed little improvement (Participants 3, 8, 10). On the other hand, several
of the learners whose score was lower than average in the pretest showed a greater than

average improvement rate (Participants 2, 4, 12, 13, 14).

116

__i

 

Table 6.3
Mean percentage of perception accuracy in pretest and posttest, and improvement rate for

participants in the AV-group

 

 

Participants Pretest Posttest Improvement
(%) (%) rate (%)
1 59 86 46
2 50 86 72
3 79 85 9
4 41 88 1 1 5
5 64 75 17
6 50 68 36
7 73 92 26
8 90 96 7
9 71 77 8
10 86 92 7
1 1 59 63 7
12 27 92 241
1 3 50 96 92
14 32 79 147
1 5 64 96 50
Average 62 84 3 5

 

In the production test of Table 6.4, a similar pattern was found.

117

I:

Table 6.4
Mean percentage of production accuracy in pretest and posttest, and improvement rate for

participants in the AV-group

 

 

Participants Pretest Posttest Improvement
C/o) (%) rate (%)

1 12 43 258
2 3 52 1617
3 74 81 9
4 23 71 210
5 23 52 125
6 32 40 25
7 17 74 334
8 58 64 11
9 19 79 315
10 43 65 51
1 1 58 75 29
12 3 51 1583
13 33 71 115
14 21 84 298
15 42 71 69

Average 3 1 64 106

 

Participants 3, 8, 11 showed higher scores in the pretest than the average, (31%),
but a small improvement rate. The learners whose scores were lower than the average in
the pretests showed considerable improvement (Participants 1, 2, 4, 5, 7, 9, 12, 14). This
pattern was observed more often and the improvement rate was much greater in
production than perception.

The relation between perception and production was compared with Pearson’s

correlation, and a significant correlation was observed between the rates of perception
and production improvement (r=0.63 6, p=0.015). However, we observed that

considerable individual variation was found in the degree of perception and production

118

improvement.

Two categories of improvement were observed: 1) Learners who showed
perception precedence (high score in the perception pretest, but not in production
(Participants 5, 7, and 9)), and 2) Learners who showed balanced abilities and
improvement (Participants 4, 12, and 14). The latter group started lower than average in
both perception and production, but improved substantially in both domains. There were
no learners who showed a production precedence pattern (high score in production pretest,
but not in perception). Generally the perception test scores were higher than production
ones both in pretest and posttest. This result is consistent with the prediction SLM makes;
production will follow perception, although this is not always the case as discussed in
Chapter 2. In addition, the observed individual variation of development showed that
these two skills did not always develop in parallel, in partial contradiction to the
prediction of SLM. Production improvement with perception training in the absence of
explicit production training supports a close link between perception and production, and

is consistent with other studies (Bradlow et al., 1997, 1999; Hardison, 2003).

6.3.7 Follow-up interview responses
At the conclusion of the training sessions, interviews were conducted with
learners to assess the training from their point of view. First, 9 out of 15 learners said that
fricative consonants were the most difficult to identify as geminates. Learners were aware
of the difficulties of distinguishing fricative geminate consonants from singletons.
All the learners mentioned their greater awareness of the difference between

singletons and geminate consonants as a result of the training sessions. Some learners

119

said that if they had not participated in this training they probably would not have known
that ‘sasu’ and ‘sassu’ are pronounced differently and might have thought these were the
same word.

Thirteen students said that they did the training with their own computer at home
at night, between dinner and sleep, and said that they liked having the choice to do the
training either at home or at school. Eleven learners responded that the training with the
visual information was helpful. One learner explicitly stated, “the picture of the sounds
gave me an idea of what I should try to listen to.” Along with the learners’ comments
on the efiectiveness of the training and the results of the posttest, their remarks indicated
that electronic visual input was helpful to draw the learners’ attention to the durational
contrasts used in the training. Attention shifts are important theoretically and help to
account for the fact that the most problematic sound for perception (i.e., /s/) showed the
greatest improvement.

Three students said they would become better if they had more training, having
realized that they still had not achieved native-like proficiency. At the same time, these
three students (Participants 4, 12, 13) had actually shown substantial improvement.
Considering the fact that all learners had volunteered for the training, it can be said that
they were very motivated to improve their Japanese; however, these three students were
sufficiently motivated to express willingness to participate in additional training
sessions if they were offered. This may indicate a correlation between learners’

motivation and development, as discussed in the literature.

120

 

 

6.4 Discussion

the results of Experiment IV showed significant improvement in perception
accuracy with AV training using electronic visual input. In addition, this improvement
generalized to novel stimuli and a new talker. The A-only group showed less
improvement from the pretest to the posttest than the AV-group. This result, showing the
effectiveness of visual information in improving L2 phonology, replicated the results of

several previous studies (e. g., de Bot, 1983; Hardison, 2003, 2004).

 

The detailed examination of the data of the AV-group revealed that perception of
geminate consonants improved under various phonetic contexts. The training was
effective in improvement of the perception of all three consonant types at both the word-
and sentence-level. More importantly, the data showed a greater improvement under the
conditions which were most difficult in the pre-training perception of geminates, which
were examined in Experiment I; learners showed the most difficulty in perceiving /Ss/
geminates, especially followed by the lower-sonority vowel /u/. This combination, /ss/ +
/u/, showed the lowest score in the pretest, but a much greater improvement was noted for
this condition in the posttest. Further, the perception data in Experiment I showed that the
learners had more difficulty in sentence-level than word-level perception, but the score
for sentence-level perception exceeded that for word-level perception in the posttest. The
results indicated that the AV-training was especially effective in improvement of
perception of the geminate consonants under the conditions that are the most difficult for
the learners.

Hardison (2003) also reported a similar finding. In her study of /r/-/l/ contrasts in

English, visual input contributed the most to the perception of the sounds in the more

121

 

difficult environments, which were utterance-initial for the Japanese subjects, and
syllable-final for the Koreans. These difficulty ratings were based on pretest
identification accuracy and predictions from analyses of their L1 phonology. The present
study can be added to the evidence that shows that training with visual input is effective,
especially with sounds that are difficult for learners.

Another important finding is that the scores for production intelligibility also
improved from pretest to posttest. Since no explicit production training was provided, this
improvement is most likely due to the perception training. Both the AV-group and the
A-only group showed significant improvement in production. The improvement in
production for the training groups was consistent with previous findings (e.g.,
Akahane-Yamada, 1999; Bradlow, Pisoni, Akahane-Yamada & Tohkura, 1997 ; Hardison,
2003; Rochet, 1995). The results of these studies indicated that training in Speech
perception could transfer to improvement in the production domain. However, the mean
score of the AV-group in the present experiment was significantly better than that of the
A-only group. Thus, we could observe a greater effectiveness of perception training with
electronic visual input on this transfer efl’ect. It was also important that the improvement
of /s/ was very high; almost tied to /k/, which was the highest. Since the greatest
perception improvement was also found for /s/, a close perception-production link was
indicated.

As expected from the results of previous studies, the result of this experiment also
indicated a close connection between the speech perception and production domains, in
this case, in the process of the acquisition of Japanese geminates by English speakers.

As hypothesized, the result of the training was compatible with the learning

122

process captured by an episodic model framework. As reviewed in Chapter 2, multiple
trace theory assumes that all attended perceptual details of events are stored as traces in
memory (Hardison, 2000, 2003; Hintzman, 1986). In Experiment IV, the visual input of
Speech waveforms of geminate consonants succeeded in drawing learners’ attention, and
the repetition of the stimuli in various phonetic contexts encountered through the
two-week training sessions formed the bases of the episodic memory (Hintzman, 1986).
The attended feature was mora weight of Singletons and geminate consonants, which was
presented to the learners through the speech waveforms, and as a result, a weighting
scheme was developed to accommodate detection of such features in Japanese. The result
of the generalization test also indicated that learning had taken place in terms of the
formation of more clearly defined memory traces to which new input could be matched
for identification.

In sum, the results of the present experiments indicate that 1) computer-based
perceptual training with visual information (i.e., waveforms of geminate consonants)
showed a greater advantage over auditory-only training, 2) adult learners can be trained
in the perception of geminate consonants in Japanese, and 3) this ability is closely related
to their L2 speech production. A firrther pedagogical implication is that web-delivered
perceptual training, as examined in the present experiment, can be practically

incorporated into classroom teaching.

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CHAPTER 7

CONCLUSION

7.1 Summary of findings

The present study has reported on data from the perception and production of
geminate consonants in Japanese by American learners. Based on these data, an effective
way to train learners to improve their perception and production was developed and
tested. The following is a summary of the findings with reference to the research
questions proposed for this study.

The first research question addressed the issue of the way that the learners
perceive and produce geminate consonants. The question of whether there any particular
phonetic contexts and identities of geminate consonant which make perception and/or
production more difficult for learners was investigated. The findings of Experiments I
and HI, both in the perception and production data, showed that the learners were affected
by the phonetic contexts and identities of geminate consonants, and the degree of
difficulty in perception and production varied depending on the types of consonants and
the phonetic environments.

The second research question investigated whether audio-visual training would be
more beneficial than auditory-only training by comparing audio-visual training using
visual display of waveform of geminate consonants to audio-only training. Experiments
II and IV conducted a comparison of pretest and posttest scores, and the result indicated
that the learners could be trained to improve perception by means of a training program

with electronic visual input as well as auditory-only training; however, the effect of

124

AV-training showed its superiority in producing such improvement over the A-only
training.

The third research question examined the relationship between perception and
production development. It was investigated whether perceptual training would improve
production ability without any explicit production training. In Experiment IV, the
learners did not receive any explicit production training; however, the learners improved
in production ability. Overall, the AV-training group data showed a significant
correlation in their improvement of perception and in their improvement of production.
However, data from individuals revealed that learning rates varied considerably among
the learners. Some learners showed greater development in perception and others Showed
balanced improvement, in which perception and production improved equally. This result
indicates that these two skills do not always develop in parallel, but we can still conclude

that there is a close link between perception and production development processes.

7.2. General discussion

The perception results of Experiment I Showed that the learners had difficulties in
perceiving geminate consonants, particularly in certain phonetic contexts: geminate
consonants /CC/ + high vowel /u/ were more difficult to perceive than geminate
consonants /CC/ + low vowel /a/. It is suggested that the lower sonority of /u/ made
perception of the geminate more diflicult since the difference between a consonant (the
geminate) and a more sonorous environment would be more salient, highlighting the
boundary between the consonant and the vowel and thus making the precise duration of

the consonant easier to perceive. On the other hand, the preceding segment, either a

125

consonant + vowel or a vowel alone, did not affect perception of geminate consonants. It
was also revealed that the learners found a geminate consonant read in a sentence frame
more difficult to perceive than one read in isolation. This result indicated that it was
necessary to include sentence-level stimuli in both research and training, while many of
the previous studies of geminate consonants in Japanese used only words in isolation
(e.g., Enomoto, 1992; Fukui, 1978; Minagawa & Kiritani, 1996).

The types of consonants also had an effect: fricatives (/ss/) were more difficult to
perceive as geminates than stops (lkk/ and /tt/). Further, there were many learners who
misperceived fricative geminate consonants as long vowels. Previous studies indicated
only that the learners’ errors in perceiving geminate consonants were failure to allocate
mora weight correctly, taking geminates for single consonants. However, the present
results indicated a possibility that even the learners who made errors can at least perceive
the correct number of morae. In other words, they could allocate the correct mora weight,
but had trouble with attributing it to the correct segment.

In Experiment H, an alternative to traditional laboratory auditory training as a
way to train learners was tested. Based on the perception data in Experiment 1, electronic
visual input which displayed the frication noise of fricative geminate consonants visually
on a computer screen was tested to examine whether it could improve the learners’
perception of geminate consonants. Many studies have been conducted to examine if
visual feedback was effective in improving production of new L2 phones at both word
and sentence levels. The studies showed that such feedback was successful in improving
the learners’ production. Experiment 11, however, focused on perceptual training by

displaying waveforms, and the result indicated a significant effect for such visual input in

126

 

improving learners’ perception.
Experiment IH showed that the learners’ production was also affected by some
phonetic conditions. The type of the preceding segment brought about a significant
difference; when a consonant + vowel (Isa!) came before a geminate consonant, the
learners had more difficulty in production than when only a vowel (/a/) preceded. The
effect of sonority was not observed in production. As for the consonant types, production 1-

of /kk/ was significantly easier than that of the other two consonants (Iss/ and /tt/), which

1":

seemed to be equally difficult. Comparison between word-level and sentence-level
production showed slightly better accuracy for the latter. For the learners in the present
study, who were at the very beginning levels of learning Japanese, reading sentences
might be more difficult and have required much more attention, which might have led to
a better score.

Experiment IV, which used display of waveforms as visual input, involved a
two-week training program. An AV-group was given instruction on geminate consonants
with accompanying waveform displays, and an A-only group was given only auditory
training in the pretest and posttest design. The result indicated that both training groups
showed improvement, but the AV-group’s improvement was significantly greater than
that of the A-only group; this result could be attributed to the electronic visual input.

The detailed analysis of the AV-group data revealed that the training had an effect
on the learners’ ability to perceive geminate consonants under the conditions which were
found to be specially in the perception data of Experiment 1. Before the training, the
lower accuracy scores indicated that the learners had particular problems with perceiving

geminate consonants in fi'ame sentences, geminate fiicatives, and geminates before /u/.

127

However, the posttest score showed that perception of these geminates improved even
more dramatically than the others. In addition, the effect of training seems to have been
generalized to tokens with combinations of new consonants and vowels spoken by an
unfamiliar voice which the learners had not encountered in the training sessions.

Another important finding of the present study is that the effect of the perceptual
training transferred to improvement in production. No explicit production training was
given to the learners, but the production test indicated a Significant improvement after the
training. In the pretest, the learners apparently had difliculty with timing control since
most of the errors were made by misallocating mora weight and misperceiving a
geminate consonant as a Singleton. After the training, such errors were reduced. The
learners were able to produce durational contrasts to some extent. Some previous studies
also found such transfer effects of perception training on production, for example, the
/r/-/l/ contrast in English by Japanese speakers (Bradlow et al., 1997) and the VOT of the
/bu/-/pu/ contrast in French by Chinese speakers (Rochet, 1995). Hardison (2003) also
reported that such an effect was found in the training of /r/-/l/ contrasts with AV input
including a talker’s facial cues. The present study revealed that a transfer effect could
also be found in the acquisition of durational differences, which no previous studies had
referred to. Together with other previous studies, we can conclude that development of
phonetic categories is achieved through intricate communication between the perception
domain and the production domain.

The results of our training studies are compatible with the view that

developmental change and associated perceptual reorganization in speech perception is

primarily due to modification of selective attention to linguistically related mechanisms.

128

 

 

The importance of attentional process in identification, categorization, and discrimination
of speech signals has been acknowledged by many researchers in first and second
language acquisition. According to Jusczyk’s (1993) model of the development process of
infant speech perception, infants have an innate auditory analyzer which provides a
preliminary description of the spectral and temporal features present in the acoustic signal.
The output of the auditory analyzers is weighted to give prominence to the most critical
distinctive features. This weighting scheme is a way of directing attention to critical
features for recognizing and distinguishing words in a particular native language. L2
learners must reorganize the weighting scheme which is used for the native language so
that a new weighting scheme optimal for L2 can be developed. They must learn to alter
the focus of attention, which affects the way in which speech sounds are perceived.
Nosofsky (1986)’s study, based on an experiment using multidimensional visual stimuli,
showed that selective attention to specific stimulus dimensions can modify the learners’
psychological space, which leads two novel phones to be represented as similar (a shrink
in dimensions) or dissimilar (a stretch) in the psychological space. For example, when
comparing two objects that differ in size, weight, and color, if size is the critical
dimension for comparing the two objects, then a learner will give more weight to fine
gradations along this dimension and less weight to the other dimensions. Thus, in the case
of Japanese, it is necessary to give weight to the duration dimension to identify the
difference between a singleton and a geminate consonant.

In the field of SLA study, based on Nosofsky’s study, Pisoni et al. (1994) showed
that adult L2 learner’s attentive processes can be modified based on their prior linguistic

experience, which will lead to better discrimination of phonetic contrasts not present in

129

 

 

 

their L1. Successful training as linguistic experience will affect perception by modifying
learners’ attentional processes so that reorganization of psychological dimensions and
changes in the weighing scheme of different acoustic cues appropriate to the novel
categories can take place (Logan et al., 1991). Guion and Pederson (2002) examined the
role of attention in phonetic category formation by manipulating attention shift.
Participants oriented to phonetic information demonstrated greater learning of trained
novel phonetic categories, whereas participants oriented to semantic information
demonstrated greater learning of meaning. This result indicates that ‘different instructions
gave different “weighting” to the importance of orienting to phonetic or semantic features
of the stimuli during training presentation’ (p. 17). They assumed that these different
weightings could result in either greater signal detection or greater manipulation in
working memory. Apparently the orientation to phonetics increases successful detection
of the relevant features of the sounds being trained.

As we have observed in Experiment I, the perception data indicated that the
beginning level learners were at the stage where their L1 processing cues (the
syllabification strategy of English) were competing with L2 timing cues (mora weight
assignment in Japanese). Many of the learners had troubles with allocation of length, and
even those who could allocate the length had troubles with attributing it to the appropriate
segment. Explicit instruction through visual input of speech waveforms raised the
learners’ awareness of their troubles with length allocation and attribution and firrther
facilitated the shift of their attention to the critical cue to identify contrasts, in this case,
singletons and geminate consonants, through visualization during the training. It is

assumed that the learners’ psychological space was modified favoring the identification

130

 

 

 

of durational contrasts.

 

When modification of the perceived psychological Spacing among dimensions
occurs, there are also changes in the memory representations with regard to the
psychologically more salient dimensions (Pisoni et al., 1994). Evidence from previous
studies has shown that L2 learners were encoding very specific and detailed contextual

information about the acoustic cues of speech sounds in the different phonetic .

”ea

environments, which is consistent with the episodic view of memory encoding and
categorization. Unlike the traditional ab stractionist view, which assumes that the speech
signals are filtered and irrelevant information for processing such as voice details is
discarded as noise, the episodic view holds that all tokens of a category are equally
available for processing and learning, as seen in multiple-trace theory (e.g., Hintzman,
1986), which assumes that no such normalization process before memory storing.
Evidence showed that listeners store detailed memories which include seemingly
irrelevant information, such as the exact wording of sentences (Begg, 1971) and exact
word format (upper case or lower case in writing; Hintzman, Block & Inskeep, 197 2).
In multiple-trace theory, traces of the individual episodes are stored, and
aggregates of traces activate in concert at the time of memory retrieval (Hintzman, 1986).
This aggregate represents the category as a whole. A number of repetitions of the stimuli
presented as various tokens through the training are stored as the traces of each of all the
experiences, which they heard and saw as the stimuli in the training; these traces were
preserved as primitive properties in PM at the time of stimulus input. After this
preservation, the probe or retrieval cue is sent fi'om PM to all traces in SM and PM can

receive a single reply or echo back from SM.

131

As reviewed in Chapter 2, Hardison (2000) proposed scenario of bimodal L2
speech processing and the role of training based on multiple-trace theory. After auditory
and visual inputs are preliminarily analyzed through the innate auditory analyzer, a new
weighting scheme for L2 must be developed, so that learners can alter their attentions
from the optimal setting to perceive distinctive features in L1 to the optimal setting to
perceive distinctive features in L2 by learning to attend to new sources of information
obtained through the auditory analyzers. Through training, the features of an experience
are copied into a trace. Probes, or signals processed in PM, activate already stored traces
in SM, and the weighting process occurs according to the trace’s similarity to the features
of the probe, which ultimately will return an echo to PM. Attention to auditory and visual
attributes of the stimulus will determine the features of the probe. Training with multiple
exemplars and immediate feedback enhances learning; repetition and feedback can direct
attention to critical features of the speech signal and modify the memory system. As the
result of learning, new L2 memory traces become less ambiguous and less confusable.

Thus, the objective of L2 perceptual training is ‘to create a situation in which the echo

from an aggregate of L2 traces acting in concert overshadows the echo from L1 traces’ (p.

320), since training should direct attention to the distinctive features of the L2 input in
order to distinguish them fiom those of the distinctive features of the L1 system. A great
similarity between the L2 input and stored L1 traces causes an ambiguous echo to be
returned to PM; therefore, the greater opportunity to create a weighting scheme that shifts
learners’ attention to the critical auditory and/or visual stimulus properties makes it
possible to encode less ambiguous L2 traces in memory.

The visual input of the present study serves as an explicit instruction to orient the

132

let‘w
I

 

learners’ attention to allocation and attribution of length. Through the trainings, new
traces were created and stored. The traces were copies of the detailed information about
geminate consonants in different contexts, instead of forming a prototype as a single
representation of a geminate consonant. A new episodic trace in PM send a probe to
search for a good match in SM. When a match is made, an echo is sent back from SM
through analogy between the new trace and the stored traces. A better echo or a better
match can be achieved if the content of the echo is accurate and strong. Through
encountering the stimuli in various contexts many times through training, the echo
becomes sharper and stronger and enhances a better match. It is assumed that in general,
good learners might get better at searching for a good match through such training. On
the other hand, weak learners have weak memory, and analogy is difficult, so that a good
match cannot be sent back.

Works such as Pisoni and colleagues (e.g., 1991) and Hardison (e. g., 2003) used
varied stimuli with regard to voice, vocalic context, and word position in training, thus
exposing the learners to the variability of stimulus which could be encountered in the real
world. The results of the training support the hypothesis that memory encoding of speech
involves storage of individual episOdes, preserving both contextual variability and
indexical properties of speech, rather than abstract prototypes. Strange and Dittman
(1984) showed that the subjects who received low variability training failed to generalize
the effect of the training to new tokens, but high variability stimuli produced successfirl
results. The present study also used geminate consonants in various phonetic contexts as
stimuli; different consonants were used with different preceding and following vowels, in

different grammatical constructions (words in isolation and in sentence frames).

133

 

Perception data in Experiment I indicated that the learners’ perception ability varied
depending on the phonetic context and identities of geminate consonants; therefore, the
result of the perception test indicated that geminate consonants are not all the same in
terms of perceptibility. When the phonetic context, such as surrounding vowels differed,
and when different types of consonants were used, learners perceived each geminate
consonant in different ways, so that it is necessary to consider all these various contexts.

de Sa and Ballard (1997) argue that the co-occurrence of multi-sensory signals
can assist processing. They showed through psychophysical studies that information from
one modality can assist classification in another and the physiological evidence supports
this finding in showing that input to one of the modalities can influence processing in
another sensory pathway, in spite of neurophysiological and psychophysical evidence
which indicated each modality has its own processing stream. Difl’erent modalities have
access to each other’s output at a higher level at the early stage of processing but can
reach the lower levels within each processing stream through mutual feedback, which
suggests that this information is coming top-down through feedback pathways from
multi-sensory areas. It is also suggested that this integration may not only afi’ect the
properties of developed systems but also play an important role in the learning process
itself. The visual and auditory stimuli are able to interact to produce a unified perception,
which is assumed to be copied to a trace.

Taken together, the visual input and the auditory stimuli used for the present
study enhanced learning by raising learners’ attention to the distinctive feature of mora
weight in geminate consonants, which eventually modified the learners’ weighting

scheme. The experience or episode through training was enhanced through auditory and

134

 

visual sensory feedback, stored as trace, which returned a clearer, less ambiguous echo
through training. The effectiveness of the training can be accounted for by an episodic

view of learning such as that suggested by multiple-trace theory.

7.3 Limitations of the study and further study suggestions

One of the limitations of the present study is the difference between the learners’
groups in the perception data (Experiment I) and the production test (Experiment HI); the
perception data was obtained from the learners in the US. and the production data was
obtained from the learners who were studying in Japan. Although we reached some
generalization that the learners’ production as well as perception was affected by phonetic
contexts and identities of geminate consonants, a direct comparison between the
perception and production data was not conducted due to this difference. While
Experiment IV showed some links between the learners’ perception and production
abilities by demonstrating the transfer effect fi'om perceptual training to production
improvement, firrther research needs to be conducted on the same subject group to
investigate the relationship between these two abilities more closely, and see whether
there would be any common different contexts and types of geminate consonants,
specially because there is no previous study of such comparison regarding geminate
consonants in Japanese.

Second, the participants in the training study were limited to beginning learners to
avoid previous knowledge of the stimulus; however, it is also important to examine the
interaction between learners’ knowledge of the meaning of words containing geminate

consonants and perception ability of them. While most of the previous Studies of the

135

 

 

 

perception of geminate consonants focused on acoustic factors such as absolute stop
closure duration, no studies have been done in this respect. Since this may be another
important factor besides acoustic cues for learners to perceive geminate consonants in
natural settings, further investigation would be necessary.

There are many other possibilities to expand the training studies. For example, the
training in the present study Showed the effect on improvement in perception of geminate
consonants, but it is worth examining whether the same effect would be found on other
types of difficult durational contrasts in Japanese, i.e., long vowels (lkite/ vs. /kiite/) and
moraic nasals (fkona/ vs. /koNna/). Considering how the visual input successfully guided
the learners’ attention and promoted a new weighting scheme for the distinctive features
of the L2 input, it is assumed that the perceptual training with visual input as the one used
in this study might bring about the similar effect.

Furthermore, it may also be interesting to explore whether a focused audio-visual
presentation of another sort would achieve similar results as the present study. While in
the present study, the contribution of visual input was brought by a presentation of
speechwave forms, it is assumed that visual input to direct learners’ awareness to mora
weight contrast might be similarly effective. For example, the spelling system in Japanese

is an effective tool to indicate the numbers of mora. Geminate consonants are spelled

with small “tsu (0)” in Japanese orthography, so that /kitte/ is spelled as “ki tsu te ('5 o
T)”, while singleton /kite/ is spelled as “kite (3 'C)”. Thus, in Japanese orthography, the

number of letters Show a difference in the number of mora (3 and 2, respectively), which
might be another effective visual input to promote their awareness of durational contrasts.

Another interest for future research is to investigate the long-term retention of

136

 

learning in both perception and production after the training. Bradlow et al. (1999)
reported that three months after training of /r/-/l/ contrasts in English, the Japanese
participants maintained their improved levels of perception performance. They concluded
that the high-variability training was effective for not only the acquisition but also
retention of new segmental contrasts. In addition, the transferred improvement on
production performance through perception training was also retained. It is highly likely
that the present training program may also show a similar effect, considering the high
variability stimulus and transfer effect of another modality; hence it is worth firrther
study.

While the traditional training programs in previous studies were typically carried
out in a laboratory setting, the on-line training program of the present study could be
easily integrated into classroom teaching. One of the advantages of the on—line training
was easy and flexible access for the learners. Teachers do not have to spare class hours
for training sessions, and students can access the training materials after school, anytime
and anywhere they want to. In the post-hoc interview, many of the learners said that they
accessed the training material between 10:00 and 12:00 at night, since that was the time
when they spent leisure time in front of their computers after they did school work
required for the following day. Such easy access could reduce the learners’ psychological
burden, such as nervousness and pressure, and they do not have to make extra effort to go
and sit in a language lab at a designated time. However, in exchange for such flexibility,
there is a drawback for research purposes; without the presence of an observer, there is no
way to watch and control the amount and frequency of training learners really take. Login

systems with a password and tracking systems to monitor students’ attended training

137

 

duration might be a solution, though it might require more specialized knowledge for the
teacher to create such a program. This might risk losing another advantage of the training
program of the present study; creating on-line materials such as the ones used in the
present study does not require any Special equipment, while the laboratory setting is
costly and requires Special skills and knowledge to manage it. Hence, additional research
is required to avoid sacrificing such advantages, while developing more advanced
program to monitor learners.

Further, the results indicated that the effect of training in perception transferred to
improvement in production. Some studies have also reported a transfer effect, but with
the opposite tendency; that is, production training brought about an improvement in
perception, as reviewed in Chapter 2. According to Rochet (1995), either perception
training or production training could be equally effective to improve ability in the other
Skill. However, considering the difficulty in creating automated feedback programs to
respond to learners’ production, perception training would be more realistic for
instructors. Akahane-Yamada, Tohkura, Bradlow, and Pisoni (1996) also suggest that
since computer-based training in production is more difficult than that in perception,
‘tuning the trainees’ speech perception’ (p. 609) will facilitate learning in production.
However, since it has been reported that production ability improved by perception
training lagged behind perception and required more time to achieve parity with
perception ability (Akahane-Yamada, 1999), it is worth exploring to what extent
productive ability can be trained through perceptual training and vice versa.

In conclusion, the results of the present experiment demonstrate that the

perception of geminate consonants by English speakers can be improved using a

138

 

perceptual training with visual input which displays speechwave forms of the target
segments. An alternative and effective way is offered to train learners of Japanese to
perceive geminate consonants as well as produce them. The result of the perceptual
training brought about improvement in the learners’ perception, which was not limited to
the tokens used in the training; the result of the generalization tests indicated the effect

could be carried over to new tokens and pronunciations by a new voice which the

‘ "a

learners were not familiar with. It is assumed that visualization with waveforms helped

III—7 .-
‘.

the learners grasp a clearer picture of durational contrasts. The present study raises many
interesting and potentially important questions about the nature of stimulus variability in
perceptual learning and its role in training nonnative listeners to perceive phonetic

contrasts that are not distinctive in their language.

139

APPENDIX A

Perception test

P_ar1_1_

You will listen to some Japanese words. Each question has 3 options. Circle the word
you’re hearing. You will hear each word only once. If you are not sure which word you
heard, make your best guess. Please do not leave any numbers unanswered. Don’t be
concerned if you don’t understand the words.

Examples:

You will hear: kitte

 

Circle: a kite

b. kiite
®. kitte
1) a. ata 5) a. taachu
b. aata b. tachuu
c. atta c. tachuu
2) a. atsu 6) a. saku
b. aatsu b. saaku
c. attsu c. sakku
3) a. kaze 7) a. asu
b. kazee b. aasu
c. kaaze c. assu
4) a. aka 8) a. aku
b. aaka b. aaku
c. akka c. akku

140

 

9)

10)

11)

12)

13)

14)

15)

16)

m

sasu

saasu

. sassu

. asa
. aasa

. assa

. saka

b. saaka

. sakka

. satsu
. S381 SL1

. sattsu

. sechi
. seechi

. seechi

sasa

. saasa

c. sassa

. kaaki

c. kakki

b.

atsu
aat SD

311 51.1

17)

18)

19)

20)

21)

22)

23)

24)

. sasa
b. saasa

. sassa

. saka
. saaka
. sakka

. aka
b. aaka
. akka

. kate
. kaate
. katte

. sasu
. saasu

. sassu

. asu
. aasu

C. assu

.saku
.sakku
.saaku

. satsu
b. saatsu

. sattsu

141

25)

26)

27)

28)

29)

30)

9’

.0

8)

0‘93

0‘93

0

ata
. aata

atta

. atsu
. aatsu

. attsu

. kakite
. kakiite
. kakkite

. asa
.aasa

. assa

. sata
. saata

. Sflffli

142

Part H

You will listen to Japanese words in frame sentences. The frame sentence is given as in
the examples. Each question has 3 options. Circle the word you’re hearing. You will hear
each word only once. If you are not sure which word you heard, make your best guess.
Please do not leave any numbers unanswered. Don’t be concerned if you don’t
understand the words.

Examples:

You will hear: kitte

Circle:
watashi wa to iimashita
a kite
b. kiite
O. kitte
l) watashi wa to iimashita 4) kore wa desu
a. ata a. sasu
b. aata b. saasu
c. atta c. sassu
2) kore wa desu 5) watashi wa to iimashita
a. asu a. kakite
b. aasu b. kaakite
c. aSSi c. kakkite
3) watashi wa to iimashita 6) kore wa desu
a. saka a. sata
b. sakka b. saata
c. saaka c. satta
7) kore wa desu 14) watashi wa to iimashita

143

.-
'-

a. aka
b. aaka
c.akka
8) watashi wa to iimashita
a. taachu
b. tachuu
c. tachuu
9) kore wa desu
a. saku
b. saaku
c. sakku
10) watashi wa to iimashita
a. tatu
b. taatsu
c. tattsu
11) kore wa desu
a. aku
b. aaku
c. akku
12) watashi wa to iimashita
a. aka
b. aaka
c. akka
13) kore wa desu
a. alcu
b. aaku
c. akku

21) kore wa desu

144

a. satsu
b. saatsu .
c. sattsu
15) kore wa desu
a. sasa
b. saasa
c. sassa
16) watashi wa to iimashita
a. ata
b. aata
c. atta
17) kore wa desu
a. keta
b. keeta
c. ketta
1 8) watashi wa to iimashita
a. sasa
b. saasa
c. sassa
19) kore wa desu
a. asa
b. aasa
c. assa
20) watashi wa to iimashita
a. atsu
b. aatsu
c. attsu

28) kore wa desu

 

 

a. sasu a. saku
b. saasu b. sakku
c. sassu c. saaku

22) watashi wa

23) kore wa

to iimashita
a. atsu
b. aatsu

c. atssu

desu

a. kaze

b. kaaze

c. kazze

24) watashi wa

25) kore wa

to iimashita
a. asu
b. aasu

c. assi

desu

a. saka
b. sakka
c. saaka

26) watashi wa

27) kore wa

to iimashita
a. asa
b. aasa

c. assa

desu

a. kate
b. kaate
c. katte

145

29) watashi wa

30) watashi wa

to iimashita

. satsu
b. saatsu

. sattsu

to iimashita

. sata
b. saata

. satta

 

APPENDIX B
Production test

Part I
Please read the following words only once and record on the provided cassette tape.

 

 

 

 

 

 

 

 

 

1. satta 2. assu 3. saka
$07”: 5209‘ '57.?)
4. aka 5. tachuu 6. sakku
215D) fat; 19> 5 3 o <
7. taatsu 8. akku 9. sasu
71:32“) 37> 0 < $79“
10. assa 11. sakka 12. kakisu
if) 0 a a o 71> 73%?
13. akka 14. aku 15. sassu
2160753 32< 30'3"
16. asu 17. kazeki 18. sasa
£163“ #113 a a a
19. takata 20. sassa 21. atta
tint: é o 3 3790 7‘:
22. attsu 23. saku 24. satsu
$900 if < E: ’3
25. atta 26. atsu 27. sattsu
$907: 35’) 30’)
28. asa 29. kakute 30. sata
El?) 2:" 7b>< “C ‘5 7‘:

146

 

PartH

Please read the following sentences only once and record on the provided cassette tape.

 

1. watashi wa sata to iimashita

1197': L121: ‘67”: kiwi/\i L7’:

2. kore wa kakute desu
I; 109121: 75‘ < 'C'CT

3. watashi wa asa to iimashita

2197: lel: 2593 (Emmi L7:

4. kore wa atta desu

ZED/Ii Flo/57.2139”

5. watashi wa atsu to iimashita

1197’: L11 tic/DE lfllfli L7”:

6. kore wa kakisu desu

:na @3363

7. watashi wa satsu to iimashita

337’: L11 éotEhl/‘i L7”:

8. kore wa saku desu
13111 E." < ”(‘3’

9. watashi wa attsu to iimashita

397‘: Lli «Too/Dchflfli L7:

10. kore wa sasa desu

:na 3363

11. watashi wa sassa to iimashita

397’: L1: $0 3 Elnlfli L7”:

147

 

 

12. kore wa takata desu

:iLl‘i 73733731“?

13. watashi wa atta to iimashita

1197’: Li: thatch/uni L7’:

14. kore wa aku desu
:ne a<c3

15. watashi wa asu to iimashita

bf: Lli 393‘): Iz‘lfli L7“:

16. kore wa sassu desu

3.171111 “(’5 07”"(“9‘

17. watashi wa kazeki to iimashita

2197‘: Li: was l: mini L7”:

18. kore wa akka desu
$171111 ZDODVCT

19. watashi wa sattsu to iimashita

7197’: LI: 5 oOElfllfli L7’:

20. kore wa sakka desu
31711212 3 0 7331“”?

21. watashi wa assa to iimashita

7197“: List 390 “£1 Elm/\i L7”:

22. kore wa sasu desu

:nu 6363

23. watashi wa akku to iimashita
397‘: LI: 3790 < (Bimini L7:

148

 

24. kore wa taatsu desu

:hlzt 7’: 6901:?”

25. watashi wa sakku to iimashita

bitLli ‘50 < Emmi L7’:

26. kore wa tachuu desu

:flfi t6©5TT

27. watashi wa aka to iimashita

397’: Lli EDME 1010i L7’:

28. kore wa saka desu
:nu emcr

29. watashi wa assu to iimashita

7197’: Li: 6903"}: WINE L7:

30. kore wa satta desu

171111 3 07:???—

149

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