Thomas Charles Bourgeois
Kerry P. Green
Inst. for Neurogen. Commun. Disord., Univ. of Arizona, Tucson, AZ 85721
During the course of a normal conversation talkers make frequent and extensive changes in speaking rate which affects the acoustic realization of both consonants and vowels. Previous research has shown that the articulation rate of a syllable influences both the production and phonetic categorization of its segmental components. However, little certainty exists regarding which portions of the syllable carry information about overall articulation rate. The present study investigated this question by editing the burst and aspiration phases from natural /bi/ and /pi/ syllables produced at a fast rate of speech, and cross-splicing them onto the same tokens produced at slow rates of speech (and vice versa). These tokens were presented to subjects for speeded classification of the initial consonant. The results indicate that subjects were sensitive to the mismatch in articulation rate between the initial burst and aspiration of the stop consonant and the remainder of the syllable created by the cross-splicing technique. Further investigation using /bi--pi/ continua created in a similar manner indicates that consonant-internal rate information is used during phonetic categorization of the stimuli. These results are discussed in the context of current issues of rate normalization and speech perception. [Work supported in part by Research and Training Center Grant No. P60 DC-01409 from the National Institute on Deafness and other Communication Disorders.]