Intonation Structure and Disfluency Detection in Stuttering

Despite traditional evidence that lexically-stressed content words are the most common loci of disfluencies in stuttered speech (Natke, et al., 2002; Prins, et al., 1991; Brown 1938), the fact that certain function words—crucially, those directly preceding stressed content words—are also disfluently produced (Au-Yeung, et al., 1998; Howell & Sackin, 2000), suggests that the actual trigger of a disfluency occurs later than the speech perturbation itself. It was hypothesized in this paper that stutterers’ disfluencies would be accompanied by more prosodic irregularities prior to the actual disfluency than would non-stutterers’ disfluencies, and that the underlying disfluencies would be triggered by metrically prominent material in the phrase. Three stutterers and their age-matched controls were recorded performing a spontaneous narration of a picture book. Results supported the hypothesis that metrically prominent, or pitch-accented, words would attract a higher rate of stuttered disfluencies than would unaccented words. Stutterers also produced a higher percentage of their disfluencies on the nuclei of words than did controls; moreover, these disfluencies attracted pitch accents more often than did those of controls, providing further evidence of anomalous derivative disfluencies surfacing in advance of underlying ones.