The Language-Specificity of Phonetic Adaptation to Talkers.

Listeners adapt efficiently to new talkers by using lexical knowledge to resolve perceptual uncertainty. This adaptation has been widely observed, both in first (L1) and in second languages (L2). Here, adaptation was tested in both the L1 and L2 of speakers of Mandarin and English, two very dissimilar languages. A sound midway between /f/ and /s/ replacing either /f/ or /s/ in Mandarin words presented for lexical decision (e.g., bu4fa3 "illegal"; kuan1song1 "loose") prompted the expected adaptation; it induced an expanded /f/ category in phoneme categorization when it had replaced /f/, but an expanded /s/ category when it had replaced /s/. Both L1 listeners and English-native listeners with L2 Mandarin showed this effect. In English, however (with e.g., traffic; insane), we observed adaptation in L1 but not in L2; Mandarin-native listeners, despite scoring highly in the English lexical decision training, did not adapt their category boundaries for /f/ and /s/. Whether the ambiguous sound appeared syllable-initially (as in Mandarin phonology) versus word-finally (providing more word identity information) made no difference. Perceptual learning for talker adaptation is language-specific in that successful lexically guided adaptation in one language does not guarantee adaptation in other known languages; the enabling conditions for adaptation may be multiple and diverse.

Syllabic reduction in Mandarin and English speech.

This study examined whether language specific properties may lead to cross-language differences in the degree of phonetic reduction. Rates of syllabic reduction (defined here as reduction in which the number of syllables pronounced is less than expected based on canonical form) in English and Mandarin were compared. The rate of syllabic reduction was higher in Mandarin than English. Regardless of language, open syllables participated in reduction more often than closed syllables. The prevalence of open syllables was higher in Mandarin than English, and this phonotactic difference could account for Mandarin's higher rate of syllabic reduction.

LANGUAGE- AND TALKER-DEPENDENT VARIATION IN GLOBAL FEATURES OF NATIVE AND NON-NATIVE SPEECH.

We motivate and present a corpus of scripted and spontaneous speech in both the native and the non-native language of talkers from various language backgrounds. Using corpus recordings from 11 native English and 11 late Mandarin-English bilinguals we compared speech timing across native English, native Mandarin, and Mandarin-accented English. Findings showed similarities across native Mandarin and native English in speaking rate and in reduction of the number of acoustic relative to orthographic syllables. The two languages differed in silence-to-speech ratio and in the number of words between pauses, possibly reflecting phrase-level structural differences between English and Mandarin. Non-native English had a significantly slower speaking rate and lower rate of syllable reduction than both native English and native Mandarin. But, non-native English was similar to native English in terms of silence-to-speech ratio and was similar to native Mandarin in terms of words per pause. Finally, some talker-specificity in terms of (non)optimal speech timing appeared to transfer from native to non-native speech within the Mandarin-English bilinguals. These findings provide an empirical base for testing how language-dependent, structural features combine with general features of non-native speech production and with talker-dependent features in determining foreign-language speech production.