Adaptation to time-compressed speech: Phonological determinants

Abstract

Perceptual adaptation to time-compressed speech was analyzed in two experiments. Previous research has suggested that this adaptation phenomenon is language specific and takes place at the phonological level. Moreover, it has been proposed that adaptation should only be observed for languages that are rhythmically similar. This assumption was explored by studying adaptation to different time-compressed languages in Spanish speakers. In Experiment 1, the performances of Spanishspeaking subjects who adapted to Spanish, Italian, French, English, and Japanese were compared. In Experiment 2, subjects from the same population were tested with Greek sentences compressed to two different rates. The results showed adaptation for Spanish, Italian, and Greek and no adaptation for English and Japanese, with French being an intermediate case. To account for the data, we propose that variables other than just the rhythmic properties of the languages, such as the vowel system and/or the lexical stress pattern, must be considered. The Greek data also support the view that phonological, rather than lexical, information is a determining factor in adaptation to compressed speech.The acoustic/phonetic characteristics ofspeech vary as a function ofspeaker, rate ofspeech, 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 This research was supported by grants from the Human Frontier Science Program and the Spanish Ministerio de Educacion 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. Sebastian-Galles, Universitat de Barcelona, P. de la Vall d'Hebron 171,08035 Barcelona, Spain (e-mail: sebastia@psico.psi.ub.es).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 difficult...

Discriminating languages by speech-reading

“…Previous research in adaptation to time-compressed speech has shown that listeners can generalize perceptual adaptation mechanisms to rhythmically similar languages (Sebastián-Gallés, Dupoux, Costa, & Mehler, 2000). In Sebastián-Gallés et al's (2000) study, Spanish natives were able to better understand highly time-compressed Spanish sentences if they were previously exposed to time-compressed Spanish sentences than to time-compressed English ones.…”

Perceptual learning for speech

“…These results provide some of the first evidence about where in the system perceptual learning for speech takes place-at the phonological level. Sebastián-Gallés, Dupoux, Costa, and Mehler (2000) continued the approach of using cross-language training/testing, and reported that the shared phonological properties needed for cross-language efficacy go beyond simple rhythmic structure, probably including the lexical stress pattern and vowel inventories of the languages.…”

Perceptual learning of time-compressed and natural fast speech

“…These phonetic and phonological consequences of the variations in speaking rate pose a potential problem for listeners, forcing them to constantly normalize for varying speech rate ͑Green et al., 1994;Miller et al, 1984a;Miller and Liberman, 1979͒. Apart from these latter studies on local rate effects on phonetic perception of specific phoneme contrasts, there is a body of research on more gradual adaptation to artificially time-compressed speech. Artificial time compression is a method for artificially shortening the duration of an audio signal without affecting the fundamental frequency of the signal ͑Golomb et al., 2007;Pallier et al, 1998;Sebastián-Gallés et al, 2000;Wingfield et al, 2003͒. Listeners can adapt to sentences compressed up to 38% of their original duration within 10-20 sentences ͑Dupoux and Green, 1997͒. Adaptation to this manipulation is not immediate, but takes place during exposure to a number of sentences that are initially of very poor intelligibility.…”