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Major Sharpe
25 Nov 2009
Title
Mandarin-English Bilinguals’ Production of English Voiced Onset Timing
Introduction: Research Area
The topic area is a quantitative study of voice onset time (the length of time after
a plosive before the vowel after it is produced) of Chinese speakers when pronouncing
voiceless (both aspirated and unaspirated) and voiced plosives in English. Mandarin
Chinese only has voiceless and voiceless aspirated plosives, so when the Chinese
learn English, they must learn how to properly pronounce the voiced plosives in order to
be intelligible to native speakers. A part of this process is correctly producing a plosive’s
voice onset time (VOT), since it varies across voiced and voiceless plosives in English.
The results of this study has implications for both second/foreign language
acquisition and language pedagogy. If a native Chinese learner is not explicitly taught
the VOT of English plosives, yet they do produce them correctly, then that means
people learning a second language have the ability to “acquire” such suprasegmentals.
The topic of implication for SLA is expanded by the fact that I will be comparing students
who started learning English before the age of 8 to those who started after the age of 8.
It is generally acknowledged that those who start earlier will be more likely to have more
native-like English pronunciation. Using the same example, if subjects are found to
correctly pronounce English plosives, then that means ESL teachers do not necessarily
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need to revise their teaching methods by teaching English VOT because learners are
able to acquire the correct pronunciation naturally. If the opposite proves to be true,
then there is obviously a need to explicitly teach Chinese students the VOT of English
plosives in order to help them with their intelligibility.
Aim/Justification
By doing this research, I hope to come to a conclusion about whether or not it is
productive to teach VOT to nonnative speakers. I hope to demonstrate whether
implicitly teaching English VOT to ESL learners is effective, or whether teachers should
take a more explicit approach.
Literature Review
Introduction
Individual differences in L2 pronunciation can come from a variety of sources, the
least of which is age, feedback received from peers and instructors, motivation,
satisfaction with one’s L2 level, and even the rate at which one speaks. In the past,
science would typically agree that learners acquire an L2 in largely the same ways if
their environment is the same; however, research shows the opposite to be true. In fact,
there are even individual differences in the perception of sounds that are not from one’s
L1. For example, an adult Japanese ESL learner may typically have difficulties with the
r/l distinction in English, since the two sounds exist in free variation in his or her native
language. Or he or she may not have any difficulties at all because he or she has
retained the ability to differentiate between the two sounds into adulthood. In the same
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vein, studies suggest that when bilinguals encounter sounds that are similar in their L1
and L2, they automatically assume that the two sounds are subsets of the same
discrete phoneme. While this is technically true from a purely phonological standpoint, it
is not necessarily so, as the French /b/ has a different VOT lag than the English /b/,
resulting in quite the different pronunciation. Furthermore, the fact that these sounds are
so similar can cause trouble for the L2 learner. Where one would anecdotally expect
learners to quickly and easily acquire sounds that are similar in their L1 and L2, this is
often not the case. Their pronunciation of the French /b/, for example, would be
fossilized and prevent them from producing the correct VOT for the English /b/. These
last few points give much gravity to the present study. If Mandarin-English bilinguals
consider the Mandarin /p/ and the English /b/ to be subsets of the same sound then
does that mean they will have a great amount of difficulty acquiring the true VOT lag for
the English voiced stops? And does the fact that the two sounds are so similar,
especially in intervocalic position, equate even more difficulty for the L2 learner who
wishes to overcome his or her Mandarin pronunciation?
Variations in Environment and L2 Attainment
According to Moyer (1999), previous research claims that L2 attainment is not
changed according to variations in environment, motivation, or immersion. However,
Moyer demonstrates that there are certain factors that contribute to the ultimate
attainment of L2s by learners, including age of immersion, descriptive feedback on their
language production, and motivation, all correlating with the learner’s satisfaction with
his or her L2 production. This means that there are important factors that influence L2
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learning—factors that have been largely ignored by researchers for the past several
decades. While Moyer’s study is largely qualitative, dealing with learners’ selfprescribed perceptions, Theodore et al. (2009) take on a similar subject, but apply more
quantitative data to their findings. In their study, Theodore et al. (2009) found that the
VOT lag of voiceless stops is in part determined by how quickly a person is speaking.
Unsurprisingly, this would result in the hypothesis that different people have different
VOTs because some have quicker talker rates than others. Indeed, Theodore et
al.’s(2009) study confirms this, producing evidence that VOT is not a constant between
native speakers.
Variations in VOT production may be surprising because classical foundational
literature on VOT claims the phenomenon is affected by language universals, but
Golestani & Zatorre (2009) mention another interesting phenomenon: phoneme
perception can also vary from learner to learner. The authors use Hindi dental and
retroflex stops as variations that native Hindi speakers would be able to recognize, but a
native English speaker would not necessarily be able to differentiate. The authors state,
though, that some English speakers would be able to hear the difference between these
two sounds in adulthood. And those who cannot perceive the difference between these
stops can learn to do so with minimal training. This is reassuring for the pedagog and
language learner alike, as it demonstrates that nonnative speakers can learn to hear
phonemic differences in an L2 that do not exist in their L1, where they would otherwise
consider them to be the same sound. Fowler et al. (2008) brings more good news to the
table, showing us that nonnative VOTs are not set in stone.
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According Fowler et al. (2008), an L2 speaker’s voice onset can fluctuate, in a
sense, according to how long he or she has stayed in another country. The authors give
the example of a Brazilian woman whose voice onset in Portuguese had undergone a
change due to her having lived in the United States for an extended amount of time,
almost exclusively speaking English. The woman returned to Brazil for a short while,
and during this time, her voice onset recovered most of its native qualities. Anecdotally,
we could assume that when the woman left the US, she sounded more American than
Brazilian, and when she came back to the US, she regained most of the Brazilian
accent she had lost—just to lose it again. So, our voice onsets have the ability to
change depending on whatever environment we happen to occupy at the time.
Furthermore, there are cases in which these voice onset fluctuations are practically
nonexistent simply due to the fact that a bilingual has been exposed to his or her L2 for
such an extended period of time. The most immediate example that comes to mind is
early bilinguals. Those who learn a language before the critical period may sound more
native in their pronunciation of their L2 (Moyer 1999). A perhaps more fascinating
phenomenon is the concept of overhearers, and it further demonstrates the flexible
nature of humans’ VOTs. Fowler et al. 2008 defines an overhearer as a person who
grew up surrounded by a foreign language (maybe Spanish) during his or her early
childhood without necessarily learning or speaking it. If this person decides to learn
Spanish later in life, he or she will have a near-native Spanish accent, voice onset
included. Simply having been exposed to the sound system of Spanish, he or she
acquired an almost perfect accent. Fowler et al. uses this information to claim that early
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bilinguals and nonnative speakers have very few differences between their language
perception and production.
Bilinguals’ Perceptions of Sounds
Fowler et al. (2008) note that bilingual speakers make cognitive connections
between stop consonants that are of the same class. These stop consonants, while
belonging to the same class, can vary substantially in terms of voice onset, yet
bilinguals still consider them to be variants of the same sound despite these differences
(Garcia-Sierra et al. 2009). According to Flege’s Speech Learning Model, bilingual
speakers might not even notice the difference between their L1’s and L2’s voice onset
rules, so there would not be a chance for them to formulate new phonological processes
when producing their L2 (Fowler et al. 2008). Furthermore, there is evidence that if two
sounds in a language are too similar, they will be more difficult for L2 learners to
acquire. Wode (1983) mentions this phenomenon, citing that language transfer can
occur in such a situation. Assuming Chinese intervocalic voiced stops have radically
different VOTs from English voiced stops, this means there could very well be transfer
between the two languages by Chinese-English bilinguals. Rate of acquisition can also
be affected. Major & Kim (1996) have gone so far as to develop The Similarity
Differential Rate Hypothesis, wherein they state that dissimilar sounds are acquired
more quickly than similar sounds. Considering my subjects are early bilinguals, this last
point may not carry any weight. It would depend on the amount of time it actually takes
for L2 learners to acquire old and new sounds. This raises the question about the
similarity between the Mandarin voiceless and the English voiced stops in the bilingual’s
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mind, and the problem is further compacted by studies that claim the Mandarin
voiceless stops may be more similar to the English voiced stops than previously
conceived.
Möbius (2004) briefly mentions that unaspirated Mandarin stops are more likely
to be voiced in certain phonological situations than aspirated stops. Duanmu (2000)
correlates this claim when he mentions that unvoiced Mandarin stops and fricatives can
indeed be voiced in unstressed position (emphasis added). He uses the example of
[tsʷəi pa] morphing into [tsʷai ba] (page 27). He then raises the question about whether
it would be possible for a Mandarin speaker to replace unaspirated stops with voiced
stops in all situations; unfortunately, Duanmu does not go into this issue further, so the
question is left unanswered. The fact that Duanmu does not continue discussing this
possibility, combined with the fact that his sources for Mandarin voicing are more than
50 years old, makes his claim dubious at best and warrants further research. After all,
we should know whether the studies he cited have been proven or solidified, and
whether this voiceless/voiced variation is the result of free variation or assimilation. The
change of voicing would most likely be the latter. Möbius (2004) goes on to discuss
Mandarin phonology by telling us that there are major phonotactic constraints in the
language: stops can only occur in the syllable onset and there are no consonant
clusters. These constraints mean that Mandarin stops are always surrounded by voiced
sounds, which supports the idea that an unaspirated stop could become voiced. This is
assuring for the Mandarin-English bilingual attempting to acquire proper English
pronunciation, but his or her perceptions about the quality of those consonants can play
a major part in their acquisition. Furthermore, as we have already discussed, similarity
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does not necessarily cause faculty or ease for the L2 learner. Whatever the case, this
phenomenon must be kept in mind throughout the present study, as it is entirely
possible that Mandarin-English bilinguals apply this voiceless-to-voiced rule to English,
using unaspirated stops in pre- and postvocalically and voiced stops intervocalically.
Conclusion
Fowler et al.’s (2008) findings that bilinguals consider similar sounds in L1s and
L2s to be variants raises an interesting question: what correlations would MandarinEnglish bilinguals make between their two languages? Would they consider Mandarin
voiceless stops to be equivalent to English voiced stops and Mandarin aspirated stops
to be the same as English voiceless stops? By this point, we can only assume so, due
to the previously-mentioned literature by Fowler et al. (2008), Wode (1983), and Major &
Kim (1996) which describes the linguistic processes responsible for the production and
perception of similar and dissimilar sounds by bilinguals, and Duanmu (2000) and
Möbius’s (2004) findings that state that Mandarin and English stops may be very similar
in some cases. Building upon these present theories, we can hopefully come to a
clearer answer about these questions and the phenomena behind them.
Research Questions/Hypotheses
Do Mandarin stops impede learners’ acquisition of English stops? If there is an
impediment, does my research support or oppose explicitly teaching English VOT to
ESL learners? Lastly, do male and female bilinguals show evidence of varying degree
of VOT mastery in their L2?
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I predict that Mandarin-English bilinguals’ acquisition of English stops are not
impeded by the stops in their native language, that implicitly teaching English VOT is
sufficient for ESL learners to correctly acquire it, and that males and females in fact
show no differences in their VOT production.
Methodology
20 participants will be recruited from the Ohio Program of Intensive English
(OPIE) on the Ohio University main campus. There should be 10 students from each
sex, their age will ideally be 20 or 21 years old, and they should all come from the same
class sequence, AE50, which is for intermediate learners of English. This choice in
participants should reflect the nature of the study, which will concentrate more on any
possibly overlooked variability in L2 VOT production caused by gender differences and
not so much on age differences. All participants should be native Mandarin speakers,
and they should all be from Beijing in order to eliminate regional dialect differences.
The task will be explained to each participant in English by the researcher,
though there will be a certain amount of deception in order to protect the integrity of the
study. Students will be told that they are conducting a normal session like in the OPIE
pronunciation lab, where native English speakers tutor OPIE students’ speech to help
them become intelligible. Naturally, the researcher will have each students’ permission
to record their session before any recording actually takes place. Native-speaker data in
the form of a control will come from data already collected and analyzed by Möbius
2004; however, if Möbius’s 2004 data proves to be unsatisfactory for this study, then
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native speaker data will be analyzed from an online corpus. The need for such data will
be determined at a later date.
Appendix A from Fowler et al 2008 has a nice list of 16 English phrases that the
researchers used to elicit French-English bilinguals and English monolinguals’ VOT.
The sentences show a wide variety of different English stops, and for that reason, it will
also serve my study well. If a participant misreads any sentence, they will be corrected
and asked to repeat it with the correct pronunciation or intonation. This may prove to be
exceedingly difficult early on in the study, and if this turns out to be the case, then I will
have students read the sentences out loud first, and then give their opinions about each
sentence. This will give short, spontaneous data that should ideally fill any gaps that
chronic mispronunciation might leave open, and it may turn out to be a more ideal
procedure because the VOTs of recited and spontaneous speech may change due to
the latter being more natural than manipulated.
While the students read the sentences out loud, they will be recorded with an
iMac G5 using an internal microphone. The recording software I will use is Audacity.
After a student finishes reading his or her sentences, the file will be saved as an OGG
Vorbis file—a lossless codec that should not any loss in sound fidelity. The nature of
this type of file should allow the data to be applied to different types of analysis, since I
will have the original OGG Vorbis files and not just to analyzed VOTs of the files on
hand.
Analysis
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The files will then be passed through software described by Möbius 2004 called
“get_f0” or ESPS/xwaves. According to the Möbius 2004, the software has been proven
to be just as efficient in determining VOT values as a human researcher can. I will,
therefore, leave the VOT analysis up to this software, as manual analysis is very
involved and complicated. Because my study also deals with the VOTs of speakers of
different sexes, I will put this data through the statistical software Gnu PSPP see what
kinds of trends develop.
Anticipated Problems/Limitations of the Study
First, having students read sentences out loud may result in speech that is
markedly different from natural, spontaneous speech. In order to analyze this problem, I
will have six students, three from each gender group, give me some spontaneous
speech data so that I may see whether their speech truly is different depending on if
they are reciting a text or speaking naturally. Furthermore, it is entirely possible that
Möbius 2004 overestimated the software he praised in his study. It may not be nearly as
capable at analyzing VOT as he thought. In order to minimize this limitation, I may
analyze the waveforms of a few sentences myself in order to assess the program’s
capabilities. Lastly, the other studies in which researchers analyze VOT have such a
broader scope than my study will. Fowler et al. 2008, for example, has two times the
participants I will—a truly daunting amount of data to sift through, but a scientifically
rigorous amount as well.
Expected Findings
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I expect to find that there is not so much difference between the VOT of male and
female participants. Fowler et al. 2008 already answered this question in part, but not
intentionally. In their study, they found that there was no discernible difference in the L2
VOT of men and women. However, they had an uneven ratio of females to males, so a
fairer study is worthwhile. I also expect to find that Chinese-English bilinguals do use
voiceless stops for English voiced stops when they speak, simply because they lack the
English phoneme in Mandarin. However, it is apparently true that a Mandarin
unaspirated stop can be voiced when it occurs intervocalically in an unstressed position,
presumedly in free variation, so I will need to account for this in my findings.
Conclusion
Research discussed in the literature review suggests that while a bilinguals’ NL
VOT can effect his or her L2 VOT production, it is never discussed as an impediment,
even though it contributes to marked foreign accents. Indeed, our VOT production is
elastic, changing the longer we live in a foreign country and the longer we return to our
native one. This is good news for the nonnative speaker wishing to minimize his or her
accent, or for the teacher trying to teach his or her students to do exactly that.
References
Duanmu, S. (2000). The Phonology of Standard Chinese. Oxford: Oxford University
Press.
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Fowler, C., Sramko, V., Ostry, D. J., Rowland, S. A., & Hallé, P. (2008). Cross language
phonetic influences on the speech of French-English bilinguals. Journal of
Phonetics, 36, 649–663.
Garcia-Sierra, A., Diehl, R. L., & Champlin, C. (2009). Testing the double phonemic
boundary in bilinguals. Speech Communication, 51, 369–378.
Golestani, N. & Zatorre, R. J. (2009). Individual differences in the acquisition of second
language phonology. Brain & Language, 109, 55–67.
Möbius, B. (2004). Corpus-Based Investigations on the Phonetics of Consonant
Voicing. Folia Linguistica, 38, 5–26.
Major, R.C., & Kim, E. (1996). The similarity-differential hypothesis. Language Learning,
49, 2, 275–302.
Moyer, A. (1999). Ultimate Attainment in L2 Phonology: The Critical Factors of Age,
Motivation, and Instruction. Studies in Second Language Acquisition, 21, 81–108.
Theodore, R. M. (2009). Individual talker differences in voice-onset-time: Contextual
influences. Journal of the Acoustic Society of America, 125, 3974–3982.
Wode, H. (1983). Phonology in L2 acquisition. In H. Wode (Ed.), Papers on language
acquisition, language learning, and language teaching (pp. 175–87). Heidelberg,
Germany: Groos.Appendix A
1. Ben bought some flowers and put them on his dining room table.
2. Seven hungry children crowded around the buffet.
3. Miranda’s job was boring, and she fell asleep at her desk.
4. At the store, Kate purchased a tape recorder and a new stereo.
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5. As recently as two days ago, Lucy parked her car at the grocery store, and she forgot
where she left it.
6. Fred wore a heavy parka and comfortable boots on the hike up Tabletop Mountain.
7. Driving along the turnpike, Kayla listened to polkas on the radio.
8. On his perch, the tiny bird called to his mate.
9. Braving the raging surf, Peter caught a towering wave and rode his surfboard to
shore.
10.
Over the holiday weekend, Marvin performed his magic tricks, keeping his
brother Tommy amazed and amused.
11.
Bonnie covered the stewed tomatoes and turned down the burner before starting
to work on some pies for desert.
12.
Every time he sneaked down the stairs hoping to get himself a snack, Paul’s
wife caught him and him a carrot and a piece of celery.
13.
Depressed that the dentist had found three cavities, Tim pestered his mother to
buy him some chocolate candy.
14.
While waiting for his [sic] car to be fixed, Linda watched TV.
15.
Looking through the telescope, the students saw Venus.
16.
Colin browsed in the bookstore while his sister shopped for a new briefcase.