Syntactic Clause Boundaries, Speech Timing, and Stuttering Frequency in Adult Stutterers

Nine adult male stutterers read aloud sentences designed to test influences of major syntactic boundary locations on stuttering frequency and on aspects of speech timing. The stutterers were found to produce the same durational cues to syntactic boundary location previously found in normal speech production. Like normals, stutterers lengthen the duration of a word when it occurs in clause-final position, and they are more likely to place a pause following a word if that word precedes a major syntactic boundary. Moreover, these syntactically regulated speech timing effects occurred for stuttered as well as fluent sentences, indicating that the presence of stuttering episodes did not interrupt the processing of syntactic structure in the speech production of these stutterers. Finally, there was no evidence that the presence of a major syntactic boundary led to an increase in stuttering frequency. Taken together, these results suggest that the mechanisms which underlie stuttering in adults are most likely independent of those which underlie the planning and processing of syntactic units.