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Speech carries both linguistic content – phonemes, words, sentences – and talker information, sometimes called ‘indexical information’. While talker variability materially affects language processing, it has historically been regarded as a curiosity rather than a central influence, possibly because talker variability does not fit with a conception of speech sounds as abstract categories. Despite this relegation to the periphery, a long history of research suggests that phoneme perception and talker perception are interrelated. The current review argues that speech perception itself may arise from phylogenetically earlier vocal recognition, and discusses evidence that many cues to talker identity are also cues to speech-sound identity. Rather than brushing talker differences aside, explicit examination of the role of talker variability and talker identity in language processing can illuminate our understanding of the origins of spoken language, and the nature of language representations themselves. Spoken language contains a great amount of communicative information. Speech can refer to things, but it also identifies or classifies the person speaking. This dual function links language to other types of vocal communication systems, and means that recognizing speech and recognizing speakers are intertwined. Imagine someone says the word cat. The vocal pitch of ‘cat’ is 200 Hz, and the delay between opening of the vocal tract and the beginning of vocal-cord vibration is 80 ms. The listener has to process all of this acoustic information to identify this word as ⁄ kaet ⁄ . Many would agree that the vocal pitch is relatively unimportant, while the 80-ms voice onset time is crucial because it distinguishes the phoneme ⁄ k ⁄ from the very similar phoneme ⁄ g ⁄ . But what happens to the ‘unimportant’ information? On a modular view, information not linked to phoneme identity is discarded by the speech-processing system (e.g. Liberman and Mattingly 1985). Nonetheless, details such as vocal pitch may influence comprehension because they indicate the speaker’s identity, and can refine the listener’s expectations about what particular speakers are likely to talk about. Differing theories of language processing have different accounts of talker identification. On one view, two separate, independent systems process speech and talker identification |
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