Phonetic Adaptation to Foreign-Accented Speech

140 Pages·2015·1.28 MB·English

by  Xin Xie

University of Connecticut
OpenCommons@UConn
Doctoral Dissertations University of Connecticut Graduate School
8-24-2015
Phonetic Adaptation to Foreign-Accented Speech
Xin Xie
University of Connecticut - Storrs, [email protected]
Follow this and additional works at:https://opencommons.uconn.edu/dissertations
Recommended Citation
Xie, Xin, "Phonetic Adaptation to Foreign-Accented Speech" (2015).Doctoral Dissertations. 880.
https://opencommons.uconn.edu/dissertations/880
Phonetic Adaptation to Foreign-Accented Speech
Xin Xie, PhD
University of Connecticut, 2015

Over the past few decades, there has been considerable effort to find the mechanisms through
which adult listeners can accommodate the rampant phonetic variation in natural speech. My
dissertation concerns one source of variability: phonetic variation in speech produced by
individuals with foreign accents. Mounting evidence shows that listeners not only adapt to
specific speakers by adjusting acoustic-phonetic mappings, they also sometimes generalize the
remapping to novel talkers. In this dissertation, I present a series of experiments examining the
mechanism of rapid phonetic adaptation and its generalization across talkers. I tested native-
English listeners’ adaptation to Mandarin-accented English words, focusing on /d/ in word-final
position. The first set of experiments (Experiments 1-3) investigated talker-specific adaptation. I
found that perceptual learning for speech was not just a matter of adjusting phonetic boundaries
in face of noncanonical tokens; it also promoted a reorganization of the internal category
structure. The learning resulted in changes in cue-weighting functions that may prepare listeners
for adapting to similar variation in other acoustic environments. The second set of experiments
(Experiments 4, 5A and 5B) examined generalization of learning across talkers following single-
talker exposure or multiple-talker exposure. Single-talker exposure failed to produce
generalization to a novel talker. Following multiple-talker exposure, cross-talker generalization
was evident only when the test talker (a novel talker) was acoustically similar to (one or more of)
the exposure talkers. Lastly, Experiments 6 and 7 present case studies of talker-specific
adaptation to foreign-accented speakers, showing a role of speaker intelligibility and within-
Xin Xie – University of Connecticut, 2015
talker variability in phonetic adaptation. In summary, the results of these experiments
demonstrate that the lexically-guided phonetic reorganization mechanism that substantiates the
adaptation to idiolect differences of native speakers also supports adaptation to natural foreign
accents. In addition, bottom-up similarity at the acoustic-phonetic level explains a range of
situations in which adaptation effects may or may not generalize to novel talkers. Taken together,
the findings advance our understanding of the reorganization of the perceptual architecture that
listeners experience when they adjust to unfamiliar speech.
Phonetic Adaptation to Foreign-Accented Speech
by
Xin Xie

B.S., Zhejiang University, 2009
M.A., University of Connecticut, 2014

A Dissertation
Submitted in Partial Fulfillment of the
Requirements for the Degree of
Doctor of Philosophy
at the
University of Connecticut

2015
i
Copyright by
Xin Xie

2015
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APPROVAL PAGE

Doctor of Philosophy Dissertation

Phonetic Adaptation to Foreign-Accented Speech

Presented by
Xin Xie, B.S., M.A.

Major Advisor
___________________________________________________________________
Emily B. Myers

Co-Major Advisor
___________________________________________________________________
Carol A. Fowler

Associate Advisor
___________________________________________________________________
Rachel M. Theodore

Associate Advisor
___________________________________________________________________
James S. Magnuson

University of Connecticut
2015
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ACKNOWLEDGEMENTS
I would like to express my sincere gratitude to many people who walked with me on this
journey. Without your help and support, this dissertation would not be possible. First, my deepest
gratitude goes to my committee members. I owe everything to my major advisor, Dr. Emily
Myers. Your expertise, devotion, patience and trust in me have led to the completion of this
project. You have been a great mentor and a role model that I look up to in my academic career.
Dr. Carol Fowler, you are the reason that I entered University of Connecticut in the first place.
Your advice and supervision of this work are invaluable to me. Thank you for your precious
insights and your prompt responses to all my questions throughout the years. Dr. Rachel
Theodore, you have brought in a unique perspective to this project. I am grateful for extremely
helpful discussions on research and work-life balance. Thank you for guiding and sharing. Dr.
James Magnuson, your insightful suggestions on the experiment design and valuable comments
on the draft of this dissertation have helped to put this work into a much better shape. I learned a
lot.
My gratitude also goes to other faculty members who have provided insights and support
throughout the project. Thank you, Dr. Gerry Altmann, Dr. Len Katz and Dr. Jay Rueckl for
being my reviewers and for providing critical comments. I am grateful to Dr. Adam Sheya, who
kindly offered consultation on running mixed-effects models in R. I would also like to thank my
dear and wonderful labmates and friends in the Department of Psychology, who have showed
unconditional support. I enjoy your comradeship! For administrative support, I am thankful to
Debbie Vardon and Carol Valone.
In the real world, my gratitude to my family and my friends is inexpressible. Special
thanks to Wen, Lisi, Lei and Yingying. We’ve spent the most time together under the same roof.
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You made me laugh and strive. Lastly, to whom I dedicate this work, my family. My parents,
thank you for countless days of unconditional love and devotion. Your encouragement instilled
determination in me across the Pacific. And Jiesi, you are the last piece of the jigsaw puzzle of
my life, but the first person to share my joy and frustration. Thank you for making the journey
easier and more fun. And lastly of course, thanks for being a pilot speaker in my experiments and
providing the recordings (sorry that you were not chosen as the test speaker).
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TABLE OF CONTENTS
CHAPTER 1 GENERAL INTRODUCTION 1
CHAPTER 2 PERCEPTUAL ADAPTATION TO ACCOMMODATE TALKER VARIATION 7
Talker-Specific Adaptation: What do Listeners Adapt to? 8
Generalization of Adaptation: When do Listeners Generalize to Novel Talkers? 14
Limits of Phonetic Adaptation: What Kind of Speech Input is Required? 18
Characteristics of Mandarin-Accented English 21
CHAPTER 3 THE SCOPE OF PHONETIC REORGANIZATION: 24
ADAPTATION RESHAPES INTERNAL STRUCURE OF PHONETIC CATEGORIES 24
Experiment 1 25
Experiment 2 34
Experiment 3 38
Phonetic Adjustment: a Re-Weighting of Acoustic Cues 43
CHAPTER 4 THE MECHANISM OF CROSS-TALKER GENERALIZATION: 50
ACOUSTIC SIMILARITY SUPPORTS GENERALIZATION TO NOVEL TALKERS 50
Experiment 4 53
Experiment 5A 63
Experiment 5B 74
CHAPTER 5 THE LIMITS OF PHONETIC ADAPTATION 82
Experiment 6 83
Experiment 7 87
CHAPTER 6 GENERAL DICUSSION 92
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What is Reorganized during Talker-Specific Adaptation? 93
At Which Level does Adaptation Occur? 94
When do Listeners Generalize across Talkers? 96
What are the Effects of Phonetic Reorganization on Lexical Access? 99
Theoretical Implications and Future Directions 100
REFERENCES 110
APPENDICES 123
Appendix A Intelligibility Tests for Mandarin Speakers 123
Appendix B Experiment Materials 126
Appendix C Experiment Results 127
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