Speaking fundamental frequency characteristics of stutterers and nonstutterers.

This study examined certain parameters of speaking fundamental frequency (SFF) associated with stutterers' and nonstutterers' fluent production of a declarative and an interrogative utterance. Ten adult male stutterers were matched according to age and average SFF with 10 adult male nonstutterers. Analysis of the waveform data from the experimental utterances showed that the nonstutterers produced a significantly greater range of frequencies than did the stutterers across both utterances. The parameters of mean SFF, mean rate of frequency change, and mean number of frequency shifts were not significantly different between the groups. The findings of this study are in general agreement with the results of previous investigations in this area. The consistency of the findings across several studies seems to indicate that reductions in stutterers' SFF variability may be one vocal tract behavior that could serve to distinguish between stutterers' and non stutterers' fluency.