Perceptual rate normalization in naturally produced rate-varied speech.
The perception of voicing categories is affected by speaking rate, so that listeners' category boundaries on a VOT continuum shift to a lower value when syllable duration decreases [Miller and Volaitis, Percept. Psychophys. 46, 505-512 (1989); Volaitis and Miller, J. Acoust. Soc. Am. 92, 723-735 (1992)]. Previous rate normalization effects have been found using artificially varied stimuli. This study examines the effect of speech rate on voicing categorization in naturally produced rate-varied speech. The stimuli contained natural decreases in VOT with faster speech rates so that VOT values for /b/ and /p/ overlapped at the fastest rates. Consonant identification results showed that the rate effects on the perceptual boundary between /p/ and /b/ very closely matched the effects of rate on the productions, though there was a small mismatch with fast rate productions whereby voiced stops were systematically miscategorized as voiceless. Another group of listeners judged the goodness of the consonant, indicating that best exemplars were rate-varied and shifted away from the /p/-/b/ boundary. These results are discussed in light of exemplar-based and abstractionist models of speech perception.
Nagao
Kyoko
K
Department of Linguistics, Indiana University, Bloomington, Indiana 47405, USA. knagao@indiana.edu
de Jong
Kenneth
K
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D010700:Phonetics; D013061:Speech Acoustics; D013067:Speech Perception / Q000502:physiology*; D013068:Speech Production Measurement; D014831:Voice