11. Phonetics of Second and Foreign Language Acquisition

ID: 683

TONGUE CONTOURS FOR THE JAPANESE MORAIC NASAL BY
SPEAKERS OF STANDARD CHINESE
Ai Mizoguchi1, 2, Maho Morimoto3, 4, Li Weiyu3, Takayuki Arai3
1

Maebashi Institute of Technology, 2NINJAL, 3Sophia University, 4JSPS

aimizoguchi@maebashi-it.ac.jp, maho.morimoto.jp@gmail.com, w-li-5x4@eagle.sophia.ac.jp, arai@sophia.ac.jp

ABSTRACTThe Japanese moraic nasal /N/ has been transcribed
as a uvular nasal [ɴ] in the utterance final position,although variability in the place of articulation byspeaker has been reported. For L2 learners whose L1is English, /N/ is often produced as [n], avoiding an
unfamiliar place of articulation. The current study
investigated the tongue contours for /N/ by native
speakers of Standard Chinese learning Japanese using
ultrasound to analyze whether the same avoidance
strategy is applied for learners with different L1s.The
results showed that two of four speakers used [n] for/N/, while one speaker created a tongue blade
constriction and one showed a tongue back gesture. Itwas unclear whether proficiency level affected theirarticulation because even an advanced learnershowed /n/ substitution. English and Chinese
speakers seem to have different acquisition processes
and strategies for unfamiliar phonemes.
Keywords: Japanese moraic nasal, Standard Chinese,
L2, articulation, ultrasound.
1. INTRODUCTION
A Japanese coda nasal, also called a moraic nasal, /N/,
which forms a mora on its own, has often beentranscribed as a uvular nasal, [ɴ], in the utterance final
position [1–3]. Recent articulatory studies haverevealed the variability in its place of articulation byspeakers from the alveolar ridge to the uvula [4–6],
although most speakers produce /N/ as a velar or
uvular nasal.
By contrast, for learners of Japanese, it has been
observed that /N/ is produced as an alveolar nasal, [n],by native speakers of English [7]. This is probably
because there is no uvular sound in the English
phoneme inventory and thus native English speakers
use a peripheral variation of /N/, which is used in their
L1. As all three speakers including an advanced
learner have been found to use [n] for /N/ in [7], thisseems to be a robust characteristic for learners ofJapanese.
To investigate whether this strategy of avoiding an
unfamiliar place of articulation is universal acrosslanguages, the current study observed the tongue

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contours for /N/ uttered by native speakers ofStandard Chinese, which also has no uvular sound.
Standard Chinese has two coda nasals, /n/ and /ŋ/.
The coda /n/ is often produced with a weakerconstriction than the onset /n/, resulting in an
incomplete closure at the alveolar ridge [8, 9]. The
current study first investigated the tongue contours
for the Chinese coda nasals and then compared themwith the tongue contours for the Japanese moraic
nasal uttered by the same speakers. It was
hypothesized that Standard Chinese speakers
substitute /n/ for the Japanese /N/, as English speakers
do.
2. METHODS
2.1. Participants

Six native Standard Chinese speakers (3 males and 3females) who had been learning Japanese participatedin the experiment. Of these, four participants wereincluded in the current analysis to compare learnersof different proficiency levels. Two were advancedlearners (ACF02 and ACM02), while the other two
self-reported as basic-level learners (ACF03 andACM03). The advanced learners had lived in Japan
more than three years and reached the highest level(N1) in the Japanese-Language Proficiency Test. The
basic-level learners had lived in Japan for fewer thanfour months. Two speakers were from Beijing(ACF03 and ACM03), one speaker was from Dalian(ACF02), and one speaker was from Inner Mongolia(ACM02). A speaker ID prefix ‘ACF’ was used forfemale speakers and ‘ACM’ was used for malespeakers. In addition, three native speakers ofJapanese (2 females and 1 male) participated in theexperiment for comparison purposes, although thearticulatory analysis was not conducted for thecurrent study.
The participants were recruited by the authors andwere compensated for their participation in the study.
They consented to the experimental procedure
approved by the ethics committee of Sophia
University. They were in their 20s, had no history ofspeech/hearing impairment, and had corrected-tonormal vision. Language background information
about the participants was collected using aquestionnaire.

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2.2. Speech materials

The speech materials consisted of 29 Chinese words
and 15 Japanese words including nasal consonants
preceded and followed by a low-vowel /a/ with andwithout oral consonants designed for a broad analysis.
For the current investigation, four Chinese words andone Japanese word were analyzed. The target
phonemes were the Chinese onset /t/ in /an.ta/ (安打[ān.tǎ] ‘a hit’), onset /n/ in /an.na/ (安娜 [ān.nà]‘Anna’), coda /n/ in /an.an/ (暗暗 [àn.àn] ‘secretly’),coda /ŋ/ in /aŋ.aŋ/ (昂昂 [áŋ.áŋ] ‘brave-looking’), andthe Japanese coda /N/ in /kaN.aN/ (勘案 ([kaɴ.aɴ]‘consideration’). The Chinese onset /t/ and onset /n/were used for comparison purposes. The participants
read aloud the words displayed on the screen one at atime. The Chinese words were written in Chinesecharacters and the Pinyin and Japanese words werewritten in Japanese characters (Kanji and Hiragana).
The words were randomized and each word wasrepeated 10 times. The Chinese trials followed theJapanese trials after a short break.
2.3. Data collection

The audio and ultrasound recordings took place in asoundproof room. The audio signal was digitally
recorded monaurally at 22,050 Hz using a RODENT2-A microphone through an audio interface(Focusrite, Scarlett Solo 2nd Gen.), connected to alaptop computer.
Real-time mid-sagittal images of the oral cavity
were recorded with an ultrasound system (MicrUs,EXT-1H) using a microconvex probe (MC10-5R10S3). The probe was placed under the participant’s chinwith an UltraFit Headset [10] stabilizing the relative
position of the probe and head. The video frame rate
was 113 fps. The tongue images were recorded while
the speakers uttered the words and the palate images
were recorded while they swallowed water. The audio
and ultrasound video were recorded and synchronizedusing AAA software [11]. Nine tokens were excluded
from the analysis due to a synchronization error.
2.4. Analysis

The midpoint of each target phoneme from the audio
recording was measured using Praat software [12].
The tongue contours at the acoustic midpoint andpalate edge were manually traced using GetContours[13] and interpolated to 100 points on an x/ycoordinate for each frame. The origin of theultrasound fan shape was set to zero. If the tongue
images at the acoustic midpoint were unclear, then animage up to three frames before the midpoint wasused. One token was not included in the analysis due

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to poor image quality. The number of analyzed tokens
was 190 (5 target phonemes × 10 repetitions × 4
speakers − 10 excluded tokens).
The predicted tongue contours from the repetitions
were plotted by speaker for each phoneme using ageneralized additive model (GAM) [14]. The
contours were trimmed at the observed maximum andminimal points on the x-axis.
3. RESULTS
3.1. Tongue contours for the Chinese phonemes

Fig. 1 shows the predicted tongue contours with 95%
confidence intervals for the Chinese phonemes: theonset /t/, onset /n/, coda /n/, and coda /ŋ/ by speaker.
All the speakers showed a tongue front gesture for thecoda /n/ and a tongue back gesture for the coda /ŋ/.
For three of the speakers (ACF02, ACF03, andACM03), the onset /n/ showed a significant
difference around the tongue tip from the coda /n/, butno significant difference from the onset /t/. As it has
been reported [8, 9], the constrictions for the coda /n/seemed to be weaker than those for the onset /n/ forthese three speakers.

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Figure 1: The GAM contours with 95% confidence
intervals for the four Chinese phonemes: the onset /t/,onset /n/, coda /n/, and coda /ŋ/ by speaker. The gray line
above the tongue contours shows the palate contour.
3.2. Tongue contours for the Japanese moraic nasal

Fig. 2 shows the predicted tongue contours with 95%
confidence intervals for the Chinese coda /n/ andJapanese coda /N/ by speaker.
ACF02 and ACF03 showed different tongue
shapes between the Chinese coda /n/ and Japanesecoda /N/, while the other two speakers showed similar
tongue shapes for the two phonemes. ACF02 showeda tongue front gesture for the Chinese /n/ and a tongue
back gesture for the Japanese /N/. ACF03, on thecontrary, showed tongue front gestures for both theChinese /n/ and the Japanese /N/, although the tongue
blade positions differed.

Figure 2: The GAM contours with 95% confidenceintervals for the Chinese coda /n/ and Japanese coda /N/by speaker. The gray line above the tongue contours
shows the palate contour.

4. DISCUSSION
The tongue contours for the Chinese coda nasals /n/and /ŋ/ and the Japanese moraic nasal /N/ by native
speakers of Standard Chinese were investigated using
ultrasound imaging. It was confirmed that theStandard Chinese speakers used the tongue front
gesture for /n/ and tongue back gesture for /ŋ/.
Moreover, the coda /n/ had a weaker constriction thanthe onset /n/ for three of the speakers, in line with [8,9].
Two speakers (ACM02 and ACM03) showed atongue front gesture for /N/ that was similar to their/n/ articulation. One of these two speakers was anadvanced learner and the other was a basic-level
learner. This /n/ substitution for /N/ has been2624

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observed in native speakers of English [7] regardlessof their proficiency level. This suggests that, as seen
in English speakers, the Japanese moraic nasal was
not realized as a back nasal, as most Japanesespeakers do, by some of the Standard Chinese
speakers, including one advanced learner.
However, one basic-level learner (ACF03)
showed a tongue blade gesture for /N/ dissimilar from/n/ and /ŋ/. This speaker appeared to notice somedifference in /N/ but could not achieve a tongue backconstriction. It is hard to conclude whether thisspeaker misperceived /N/ as a front nasal less anterior
than /n/ or perceived /N/ as a back nasal but had
difficulty to articulate as a uvular nasal.
Furthermore, one advanced learner (ACF02)
showed a clear tongue contour difference between theChinese coda /n/ and Japanese moraic /N/. Thissuggests that the Japanese /N/ could be acquired likenative speakers of Japanese by Chinese speakers andthe /n/ substitution is not robust, as seen in English
speakers. However, it will be necessary to collect datafrom a sufficient number of speakers to draw aconclusion.
The reasons why /N/ is substituted by /n/ and not/ŋ/ remain unclear. One possible reason isorthography, as [7] pointed out. Since /N/ is often
written with ‘n’ in the Roman alphabet, learners are
already used to it when beginning to learn theJapanese writing system. Some Japanese language
textbooks for Chinese learners also use ‘n’ for theutterance final /N/ to explain the sound. However, it
seems less common to write Japanese in the Roman
alphabet than in English settings. Rather, typing
letters on computers might play a role because either‘n’ or ‘nn’ is required to type /N/ in Hiragana.
Another possible reason for the /n/ substitution is
the preceding vowel quality. In Chinese, /a/ in /an/ isa front vowel [a], whereas /a/ in /aŋ/ is a back vowel[ɑ] [9]. By contrast, /a/ in Japanese has been described
as a centralized vowel [ä] [2, 3] and few descriptions
have been reported in relation to the following
consonant. If the difference in vowel qualities
between /an/ and /aŋ/ are salient enough for Chinese
speakers to distinguish the two nasals, vowel quality
could be a cue to identify the Japanese /aN/, whose
coda consonant is unfamiliar to them. In other words,
if the Japanese /a/ in /aN/ is perceived as [a] by
Chinese speakers, they would identify the sound as/an/ and thus produce /an/ for /aN/.
To test this hypothesis, we conducted a post-hoc
acoustic analysis. Fig. 3 shows the F2 values for /a/before /n/, /ŋ/, and /N/ by the two native speakers ofChinese (ACF02 and ACM02) and two Japanese
speakers (1 female and 1 male). /an/ and /aŋ/ were
produced in the speakers’ first languages.

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Figure 3: F2 values for /a/ in /an/, /aŋ/, and /aN/.

As shown in Fig. 3, the /a/ uttered by the Chinese
speakers had higher F2 values before /n/ than /ŋ/. A
linear mixed-effects model analysis [15] and apairwise post-hoc test [16] revealed that thedifferences were significant (female: β=499.52,t=17.74, p<0.01; male: β=255.40, t=6.94, p<0.01). By
contrast, for the /a/ uttered by the Japanese speakers,
no significant differences between /an/ and /aŋ/ werefound (female: β=−46.02, t=−1.63, p=1.00; male:
β=59.60, t=1.62, p=1.00). However, there weresignificant differences between /aŋ/ and /aN/ (female:
β=132.37, t=4.70, p<0.01; male: β=118.4, t=3.21,p=0.03). A difference between /an/ and /aN/ wassignificant for the male speaker (β=178.00, t=4.83,p<0.01) and that for the female speaker approachedstatistical significance (β=86.35, t=3.07, p=0.0508),
but did not reach the conventional threshold of 0.05.
The Chinese female speaker, who was anadvanced learner and could differentiate /an/ and /aN/in articulation (Fig. 2, ACF02), had significantly
different F2 values between them (β=478.47, t=16.99,p<0.01) and similar values for /aŋ/ and /aN/(β=−21.05, t=−0.75, p=1.00). The Chinese malespeaker, who was an advanced learner but could not
differentiate /an/ and /aN/ well in articulation (Fig. 2,ACM02), had similar F2 values for them (β=48.3,t=1.31, p=1.00) and different F2 values between /aŋ/and /aN/ (β=−207.1, t=−5.62, p<0.01).
The clear difference of the nucleus vowel quality
between /an/ and /aŋ/ in Chinese implies that vowel
quality could be a cue to perceive these syllables.
However, a lack of systematic differences in theJapanese /a/ depending on the coda consonants could
result in variability among the speakers to realize theJapanese /aN/, making it harder for learners to use
such information.
5. CONCLUSION/n/ substitution for /N/ by native speakers of Standard
Chinese was observed in two of the four speakers. It
is necessary to evaluate more speakers to understandtheir acquisition processes and strategies forunfamiliar phonemes compared with speakers ofother languages.

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6. ACKNOWLEDGMENTS
This study was supported by JSPS KAKENHI Grant
Numbers JP19K13254, JP22J01381, JP23K12212,and Sophia University Special Grant for Academic
Research (Research in Priority Areas).
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