Speech Rhythm Does Not Differentiate Children Who Stutter From Peers Who Do Not Stutter: An Envelope Analysis of Self-Generated Speech.

Purpose: Developmental stuttering has been related to atypical rhythm perception and production that may affect the domain of speech. This study examined the speech rhythm of children who do (CWS) and do not stutter (CWNS) across the preschool and school-age years, using acoustic envelope measures derived from spontaneous speech samples. We further investigated age-related changes in speech rhythm and explored whether speech rhythm differs between CWS who later recovered (CWS-Rec) and those who persisted in stuttering (CWS-Per).Method: Participants were 50 CWS (38 CWS-Per; 12 CWS-Rec) and 50 age- and sex- matched CWNS ages three to twelve years. Speech was elicited during a picture-based narrative task. Envelope measures of speech rhythm were computed for non-stuttered utterances. General linear models tested effects of group and age on each rhythm measure.Results: The current analysis revealed a significant age-related increase in speech rhythm in CWS and CWNS. Results indicated that CWS-Per tended to exhibit more variable supra-syllabic rhythms compared to CWNS, while CWS-Rec showed more power in syllabic oscillations than CWNS. However, none of the measures showed statistically significant differences between CWS and CWNS or between CWS-Rec and CWS-Per.Conclusions: This study supports the notion that speech becomes increasingly more rhythmic throughout childhood and into early adolescence. CWNS, CWS-Per and CWS-Rec demonstrated similar trajectories of speech rhythm development. These findings highlight that differences in speech rhythm associated with some individuals who stutter are subtle and may become significant only after years of stuttering.