Perceptual centers as an index of speech rhythm

One of the obstacles to investigating speech rhythm has been the difficulty in locating the syllabic beat. This study attempts to address that difficulty by using perceptual centers (p‐centers) as an index of speech rhythm. P‐centers of syllables extracted from natural utterances were determined both by listeners using a method of adjustment procedure and by an acoustic p‐center model. The phonetic structure (syllabic onset) and stress patterns of the syllables in the utterances were varied, and the effects of these manipulations on the utterances’ rhythms were investigated. As expected, the p‐centers of the syllables varied systematically with their own phonetic structure. Preliminary findings indicate that the p‐center of the syllables also changes along with the p‐center of the previous or subsequent syllable so as to maintain a relatively constant interval between the two p‐centers. The study also examines the effects on rhythm of altering stress patterns, by determining whether unstressed syllables might influence p‐centers. The results will be discussed in terms of dynamic constraints which might affect speech production. [Work supported in part by National Multipurpose Research and Training Center Grant No. P60 DC‐01409 from the National Institute on Deafness and Other Communication Disorders.]