1. The 157th Meeting of Acoustical Society of America in Portland, Oregon, May 21, 2009
4pSW35. Confusion Direction Differences in Second Language Production and Perception
Yen-Chen Hao & Kenneth de Jong
&
Department of Linguistics, Indiana University
Main Points
Second language learners may display opposite
confusion directions in perception and production.
L2 learners may show different error patterns in
different prosodic locations due to the
allophonic variation in the target language.
Old category bias is only observed in
production-related tasks.
Category bias in perception and production
Frequency biasing
In perceptual identification by native speakers,
response bias typically correlated positively with
segment frequency (Silbert & de Jong, 2007).
Second language learners should be biased
towards L2 old categories since they occur
more frequently (both in L1 and L2) than the
new categories (only in L2).
Novel Category bias
de Jong et al. (2008) found that L2 learners
were biased towards old categories in
production-related tasks (Reading and Mimicry),
but biased toward novel categories, or not
biased at all, in perceptual identification.
Question
How does allophonic variation induced by different prosodic locations affect bias patterns?
Discussion
L1-L2 category mismatch
Korean EFL learners have more problems
with the allophonic variation in post-stress
position, which mismatches the L1 categories.
Post-stress position induces larger variation
in bias than pre-stress position.
Discrepancy in perception and production
Korean learners displayed different
directionality of post-stress errors in
perception and production
In perception-related tasks (Identification and
Mimicry), learners made more voiceless 
voiced errors.
In the production task (Reading), learners
made more voiced  voiceless errors.
Identification Reading
Old-New category bias
In Identification, learners have little
bias towards old (stops) and new (fricative)
categories.
In production-related tasks (Reading and
Mimicry), learners are more biased towards
the old categories (stops).
Methods
Participants
-20 Korean learners of English
-Undergraduates (22-28 years; 15 F, 5 M)
in Gyeonggi Korea (near Seoul)
-Traveled 3 months or less in English-
speaking areas
Stimuli
-10 English anterior obstruents
Similar to L1 (Old): /p, b, t, d, s/
Not similar to L1 (New): /f, v, θ, ð, z/
-Two contexts: /aCá/ & /áCa/
-Produced in isolation by 4 Midwestern
American speakers (2 male, 2 female)
Results
Bias in Identification
Large variation in bias parameter in the post-
stress context.
Post-stress position exhibits more bias
towards the voiced obstruents.
Bias in Mimicry
Post-stress: bias towards the voiced
Bias in Reading
Variation along the post-stress dimension
Post-stress: bias towards the voiceless
/áCa/
/aCá/
Orthographic /p/
prompt
Evaluation /p/
Tasks
Identification (Id)
Participants identified the obstruents from a set of 15 response options (plus “Other ____”).
2. Mimicry (Mim)
Participants listened to the stimuli and repeated after each one.
3. Reading (Rd)
Participants read same list of forms as American speakers who produced stimuli.
Evaluation
10 English native speakers judged each of the productions from Tasks 2 and 3 using similar response options as in Task 1.
Analysis
Similarity Choice Model Bias parameters (Luce, 1963), estimates of an overall tendency for a particular category to be used, were calculated for each segment
English talker /áCa/
English judge /áCa/
/áCa/
Production [p]
Production [b/p’]
Korean listener /aCa/
Korean talker /aCa/
Allophonic variation in English and Korean (hypothetical)
English
Pre-stress /aCá/
Identification /b/
response
Orthographic /b/
prompt
/aCá/
Voicing
Post-stress /áCa/
/áCa/
References
De Jong, K., Hao, Y-C., Park, H., & Silbert, N.H. (2008). The ‘[English]’ effect in acquisition of English as a second
language: Novel-category biases in second language perception and
production. JASA, 123: 3332, 2pSCc53.
Luce, R. D. (1963). Detection and recognition. In R. D. Luce, R. R. Bush, & E. Galanter (Eds.), Handbook of Mathematical Psychology (pp ). New York: John Wiley & Sons.
Silbert, N.H., and K. J. de Jong (2007). Response Bias, Type and Token Frequency, and Prosodic Context in Segment Identification. JASA, 122:3019, 3aSCa15.
Korean
Intervocalic /aCa/
Voicing
Acknowledgments
We thank Mi-Hee Cho for her help in collecting the consonant data, and Noah Silbert, and Kyoko Nagao for their work on the design, analysis, and processing of the data. Work supported by the NSF (grant #BCS ).
/aCá/
Voicing