Some effects of speaking rate on phonetic perception.

This paper reviews a series of studies on the effects of variation in speaking rate on phonetic perception, in particular, on the identification of /b/ and /w/ in syllable-initial position. The major finding of these studies was that in a variety of tasks listeners adjusted for speaking rate when using the duration of the initial formant transitions to distinguish between /b/ and /w/: At slower rates of speech, a longer transition was needed to hear /w/ rather than /b/, and conversely at faster rates of speech. This effect occurred when rate was specified by the duration and acoustic-phonetic structure of the syllable containing the target consonant and, to a more limited extent, when it was specified by the duration of a subsequent syllable. Moreover, the influence of syllable duration on the processing of transition duration was also evident in young, prearticulate infants, suggesting that at least the rudiments of a system that provides perceptual constancy across rate is part of the linguistic endowment of the infant.