Articulation rate and the duration of syllables and stress groups in connected speech.

Further analyses have been made on readings of two scripts by six talkers [T. H. Crystal and A. S. House, J. Acoust. Soc. Am. 72, 705-716 (1982); 84, 1932-1935 (1988); 83, 1553-1573 (1988)]. Durations of syllables and stress groups are compared to earlier data and various pertinent published reports, and are used to evaluate reports of articulation rate variability. The average durations of syllables of different complexity have a quasilinear dependency on the number of phones in the syllable, where the linear factor and the vowel durations are functions of stress. The duration of stress groups has a quasilinear dependency on the number of syllables and the number of phones. It was found that variability of articulation rate, measured as the average syllable duration for interpause intervals (runs), is not random, but is the natural consequence of the content of the run. Durations of comparable runs of different talkers are highly correlated. Major determinants of average syllable duration are the average number of phones per syllable and the proportion of either + stress phones or + stress syllables in the run.