Age-Related Changes in Speech Rhythm of Typically-Developing Children

Speech production displays characteristics of rhythm, including the hierarchical and nested sequencing of smaller elements, such as phonemes and syllables. Recent findings have revealed associations between deficits in rhythm and several neurodevelopmental and speech-language disorders. A better understanding of speech rhythm, including how speech rhythm may change across the school-age years and between the sexes may shed light on potential clinical markers of speech rhythm for the potential identification of speech-language disorders in children. Given the current lack of knowledge pertaining to age related changes in speech rhythm, in this study we used two different quantitative approaches to measure speech rhythm across the school-aged years with a particular focus on potential differences in speech rhythm between males and females. Speech rhythm was quantified using interval metrics, which measure the duration and variability of vocalic and consonantal utterances, as well as spectral metrics, which conceptualize rhythm as periodicity in the speech envelope. Protracted changes in numerous interval metrics and spectral metrics suggest that the speech of children generally becomes more rhythmic during the school-age years, particularly at the rate of syllable production.