Listeners’ sensitivity to talker differences in voice-onset-time: Phonetic boundaries and internal category structure

Abstract

Recent findings indicate that listeners are sensitive to talker differences in phonetic properties of speech, including voice-onset-time (VOT) in word-initial stop consonants. The current work extends our earlier research by examining the degree to which listeners adjust the initial mapping from acoustic signal to segmental representation on a talker-specific basis. Two groups of listeners are exposed to a talker producing “cane.” Word-initial VOTs are manipulated such that one group hears “cane” produced with short VOTs and the other group hears “cane” produced with relatively longer VOTs. Following training, listeners’ voicing boundary for a /g/-/k/ continuum is tested. In addition, listeners are tested on phonetic category space by rating members of the continuum for typicality as /k/. If listeners adjust segmental mapping to accommodate talker differences in phonetic properties of speech, then we expect to observe a displacement in the voicing boundaries in line with earlier exposure. Moreover, if this adjustment entails a comprehensive reorganization of phonetic category space, then the /k/ exemplars rated most prototypical will also be displaced for the two listener groups. These data will be discussed in terms of potential constraints on talker-specificity in spoken language processing.