Perception of speech rate as a function of vocal intensity and frequency.

The study was designed to examine the possibility that vocal frequency and vocal intensity influence the perception of sppech rate. One 30-second segment of spontaneous speech was used to produce nine stimulus segments that factorially varied three levels of vocal frequency and three levels of vocal intensity but were identical in speech rate. The segments were recorded backwards in pairs such that the first member of each pair was the original segment and the second was the altered segment. Eighty-eight judges were then asked to compare the speech rate of the second member of each pair with that of the first in terms of a seven-point scale that varied from "much slower" to "much faster." The results indicate that vocal frequency and intensity both separately and jointly influenced the perception of speech rate.