Doctoral Dissertation Research: Why adapt? Phonotactic learning as non-native language adaptation

Northwestern University, Evanston IL

Investigators

Abstract

In order to successfully communicate, listeners must continuously adapt to systematic differences between speakers (e.g., changing expectations about what you will hear based on a speaker's dialect). At the same time, listeners need to ignore incidental variation (e.g., if a speaker happens to be talking with their mouth full, you should not change how you expect they will speak after they have finished eating; Kraljic, Brennan, & Samuel, 2008). In this study, a series of experiments examine the limits of adaptation to novel phonotactics, or constraints on syllable structure (e.g. in English, but not Spanish, the sequence /sk/ can begin syllables, such as in the word school). This project tests the hypothesis that speakers use their past experience of phonotactic variation to distinguish systematic from incidental variation. Speakers naturally encounter variation in phonotactics between talkers of different languages, but do not encounter such variation between talkers of the same language; this predicts that speakers will only adapt to talker-specific syllable structures when exposed to talkers who differ in their language backgrounds (e.g., a native French talker and a native English talker). This hypothesis is explored in three experiments. In study 1, listeners are exposed to two talkers, each with a different phonotactic constraint, in a perception experiment. Adaptation to talker-specific constraints is predicted only when talkers differ in language background. Study 2 explores the role of talker language background on adaptation to phonotactics in speech production, using a tongue twister paradigm. Study 3 investigates the structure and granularity of listeners' prior knowledge. Can listeners hold models of only a native vs. non-native language, or can they maintain models for two separate non-native languages?