Perception and production of Mandarin-Accented English: The effect of degree of Accentedness on the Interlanguage Speech Intelligibility Benefit for Listeners (ISIB-L) and Talkers (ISIB-T)

Previous research on the Interlanguage Speech Intelligibility Benefit (ISIB) indicates nonnative listeners may have an advantage at understanding nonnative speech of talkers with the same first language (L1) due to shared interlanguage knowledge. The present study offers a comprehensive analysis of various factors that may modulate this advantage, including the proficiency of both the listeners and the talkers, the mapping of phonemes between the L1 and second language (L2), and the acoustic properties of the phones. Accuracy scores on a lexical decision task were used to investigate both native English listeners’ and native Mandarin learners’ of English perception of native English and Mandarin-accented English speech. Results show clear ISIB-L and ISIB-T effects and demonstrate the dynamic nature of ISIB effects, with both being modulated by speaker and listener proficiency. More striking ISIB effects typically occur at the most extreme ends of accentedness. Additionally, an advantage for common-phoneme over unique-phoneme words in nonnative speech was observed. While nonnative productions of common-phoneme words are more accurate than those of unique-phoneme words, for the most accented productions, nonnative listeners are faster to respond to these unique, often mispronounced, productions. The nonnative listener advantage at perceiving nonnative speech depends on various factors, including listener proficiency, speaker proficiency, phoneme characteristics, and the acoustics of specific speech tokens