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Title

Perceiving phonetic variability in accented English: A multi-level study of native and Mandarin L2 listeners

Abstract

This dissertation investigates how non-native listeners perceive and adapt to second-language (L2) accented speech. It focuses on the conditions that produce interlanguage speech intelligibility benefits (ISIB), how listeners integrate acoustic-phonetic and semantic-contextual cues during accent comprehension, and the mechanisms underlying phonetic recalibration following accent exposure.

The first study examines when listener-driven and talker-driven ISIBs emerge during the perception of English-Mandarin phonemic contrasts. It explores how L2 proficiency, native-language phonemic status, and the degree of phonological merger in accented speech affect ISIB outcomes. Both types of ISIB emerged, but their presence and strength depended on listeners’ proficiency and the cross-linguistic status of the phonemes. Low-proficiency Mandarin listeners showed advantages for English-only phonemes, but not for shared ones, indicating that ISIBs reflect L1–L2 phonological mappings shaped by L2 learning stages.

The second study explores how Mandarin-speaking L2 listeners process familiar and unfamiliar accents using both bottom-up (acoustic) and top-down (semantic) cues at the word and sentence level. It asks whether ISIBs seen in word-level tasks persist when semantic context is available. Results show that low-proficiency listeners’ advantages diminish in sentence contexts, where native and high-proficiency listeners benefit more from contextual cues. Low-proficiency listeners relied primarily on acoustic information and tolerated unfamiliar yet similar variants, suggesting emerging phonological flexibility.

The third study tests whether exposure to ambiguous speech shifts phoneme category boundaries in Mandarin-speaking L2 listeners. Both native English and Mandarin listeners recalibrated their perceptual boundaries in the same direction, but for different reasons: native listeners were influenced by acoustic/perceptual similarity, while Mandarin listeners were constrained by prior L1 phonological mergers. This asymmetry was especially evident with the fricative /θ/, illustrating how cross-linguistic mappings can limit L2 adaptation. 

Collectively, the studies show that L2 accent adaptation is driven by multiple, interacting mechanisms shaped by proficiency and experience. While shared interlanguage can aid perception, it is neither necessary nor sufficient for ISIBs. These benefits are further modulated by developmental factors, cue availability, and specific contrasts. Although L2 listeners show flexibility in phonetic processing, limited use of contextual cues may reduce this advantage in real-world settings.

Keywords: L2 speech perception; Interlanguage; Intelligibility; accent adaptation; phonetic recalibration

About the student

Danielle Deng joined the Department of Linguistics at ´óÏó´«Ã½ as a graduate student in 2017, having earned her MA at the Chinese University of Hong Kong in 2016. Danielle's research interests lie in L2 speech perception, especially in accent adaptation and word recognition. Her research into audio-visual processing explores perceivers' looking patterns when processing various types of speech information. She is a researcher at the Language and Brain Lab and the Language Learning and Development Lab. Danielle's hobbies include reading science fiction and watching sci-fi movies. See also Danielle's page and website.

Exam committee

Dr. Maite Taboada (Acting GPC)
Dr. Henny Yeung (Supervisor)
Dr. Ashley Farris-Trimble (Committee Member)
Dr. Yue Wang (Committee Member)
Dr. Christian Guibault, Department of French (External examiner)
Dr. Jessamyn Schertz, University of Toronto Mississauga (External examiner)