Acoustical durations of speech segments during stuttering adaptation

Acoustical durations of stutter- and disfluency-free speech segments from Readings #1 and #5 in an adaptation series were measured in 4 adapting, 4 nonadapting, and 4 nonstuttering subjects. The segment durations measured were intervocalic interval, stop-gap, voice onset time, and vowel duration. No clear trends in the change of acoustical durations from Reading #1 to Reading #5 distinguished the adapting, nonadapting, or nonstuttering subjects. Moreover, on the basis of speech naturalness judgements, listeners did not differentiate the Reading #1 and #5 phrase segments of subjects with high adaptation versus those with low adaptation scores. From these findings and related literature, adaptation of stuttering, as well as other fluency-inducing conditions, are viewed as circumstances that reduce demands upon central motor-linguistic processes.