Adaptation to time-compressed speech: Phonological determinants

The acoustic/phonetic characteristics of speech vary as a function of speaker, rate of speech, prosody, and so forth. Yet, when we process our native language, we are hardly ever aware of such variability; indeed, these variations are apparently dealt with automatically and effortlessly by the perceptual system. However, when processing artificially degraded speech or when listening to speakers with foreign accents, it is more difficult to make suitable adjustments. Schwab, Nusbaum, and Pisoni (1985) suggest that several sentences are required to adjust to synthetically generated speech. Anecdotally, listening to speech spoken with a foreign accent can also take some time before it becomes fully intelligible. What are the mechanisms responsible for such slow adjustments? Why are some adjustments easier than others? For instance, for a native speaker of English, English spoken with a Dutch accent seems far easier to understand than English spoken with a Japanese accent. Why? Several studies have shown that language representations in adults are, to some extent, language specific. Listeners behave as if they process speech sounds through the filter of phonemic categories of their maternal language and have difficulty processing nonnative contrasts (Best, McRoberts, & Sithole, 1988; Goto, 1971; Mann, 1986; Miyawaki et al., 1975; Pallier, Bosch, & Sebastián, 1997; Sebastián-Gallés & Soto-Faraco, 1999; Werker & Tees, 1984). Similar filters operate at the syllabic and suprasegmental levels of representation (Cutler, Mehler, Norris, & Seguí, 1983, 1989; Dupoux, Christophe, Sebastián, & Mehler, 1997; Otake, Hatano, Cutler, & Mehler, 1993; Pallier, Sebastián, Felguera, Christophe, & Mehler, 1993). Moreover, lexical access strategies are also language dependent. That is, listeners exploit languagespecific cues to find word boundaries in the continuous signal (Cutler & Norris, 1988; McQueen, Norris, & Cutler, 1994; Norris, McQueen, & Cutler, 1995). Cutler & Mehler (1993), following the proposals of Abercrombie (1967) and Pike (1946), have assumed that all of the above differences between languages can be accounted for by positing the existence of a small number of broad classes of languages, defined rhythmically. SpeThis research was supported by grants from the Human Frontier Science Program and the Spanish Ministerio de Educación y Ciencia (Contract PB97-0997) and the Catalan Government (Grup de Recerca Consolidat 5120-UB-05). We thank T. Otake (Dokkyo University), K. Forster, and M. Garrett (both at the University of Arizona) for their help in preparing and recording the Japanese and English materials. A.C. is currently at the Psychology Department, Harvard University. Correspondence concerning this article should be addressed to N. Sebastián-Gallés, Universitat de Barcelona, P. de la Vall d’Hebron 171, 08035 Barcelona, Spain (e-mail: [email protected]). Adaptation to time-compressed speech: Phonological determinants