Age-related increases in speech rhythm in typically developing children

The purpose of the current study was to examine speech rhythm in typically developing children throughout the preschool and school-aged years. A better understanding of speech rhythm during childhood and potential differences between the sexes provides insight into the development of speech-language abilities. Fifty-eight participants (29 males/29 females) aged three to nine years were included in the study. Audio recordings of participants' speech production were collected during a narrative task. Envelope-based measures, which conceptualize speech rhythm as periodicity in the acoustic envelope, were computed. Separate general linear models were performed for each of the rhythm measures. Envelope-based measures (e.g., center of envelope power, supra-syllabic band power ratio) indicated that as children aged, their speech contained more high-frequency content and became dominated by syllabic-level rhythms. Findings suggest that both sexes exhibited a similar refinement of speech rhythm as evidenced by increases in envelope-based measures, with speech production developing a more syllabic rhythmic structure during the preschool and school-age years.