Syllable internal timing: Effects on vowel and consonant duration

Abstract

The present study investigates the effects of vowel quality, postvocalic voicing, sentence position, focal stress, and speaking rate on the internal timing of syllable components. Previous findings [D. M. Behne and L. C. Nygaard, J. Acoust. Soc. Am. 90, 2254 (A) (1991); D. M. Behne and L. C. Nygaard, J. Acoust. Soc. Am. 91, 2340 (A) (1992)] have confirmed the combined effects of these factors on vowel duration and have shown that consonants can also be independently affected by sentence position, focal stress, and speaking rate. The goal of this paper is to characterize the internal timing of both component vowels and consonants when these factors affect syllable timing. Using the vowels /i,o,a,æ/, conversations were developed with /kVt/ and /kVd/ as target words. In each conversation a target word occurred in initial and final sentence position and was either focused or nonfocused by the discourse. Twelve subjects produced each conversation at three speaking rates. The results indicate that (1) speaking rate and focal stress have a global effect on syllable-internal timing, influencing both vowel and consonant durations, (2) phrase-final lengthening affects the nucleus and postvocalic consonant, and (3) postvocalic voicing and inherent vowel duration locally affect vowel duration, but have little effect on neighboring consonants. These findings verify that the factors being investigated can concurrently influence the syllable-internal timing, and suggest a hierarchy of effects on the internal-timing of a syllable, from speaking rate to inherent vowel duration.