Dialect effects in vowel perception: the role of temporal information in French

The importance of vowel duration for specifying vowel contrasts differs across languages. In English, for example, a number of vowel pairs are acoustically differentiated by both temporal and spectral information, whereas in standard French temporal information plays a much more minor role. Gottfried and Beddor (1988) reported that the effectiveness of vowel duration in perception varies accordingly: For native speakers of English, but not native speakers of standard French, a change in vowel duration affected the perceptual identity of a vowel contrast. We tested the hypothesis that the relative prominence of vowel duration within different dialects of a given language also has perceptual consequences. Vowel duration plays a much more important role in the phonological system of Swiss French than standard French. Given this, we predicted that native speakers of Swiss French, unlike native speakers of standard French, would use temporal information when identifying vowels. Our prediction was confirmed. These findings indicate that just as there are cross-language differences in fundamental aspects of speech perception, so too are there cross-dialect differences, and they support the view that the perceptual mapping between acoustic signal and vowel category is sensitive to global aspects of the listener's phonological system.