An acoustical analysis of rhythmicity in infant babbling

As a precursor to spoken language, rhythmicity in prelinguistic vocalizations can provide information on the initial characteristics of the vocal output system at the onset of first speech-like syllable use. The present study was designed to establish the temporal characteristics of syllable rhythmicity. Four typically developing infants were observed longitudinally, and acoustic analysis was made of canonical syllables to determine nonfinal syllable duration and variability. The present study also analyzed syllable duration in four English-speaking adults. Within-utterance variability of infant syllable durations was lower than across-utterance variability, indicating that though the infants produced a wide range of syllable durations, they tended to retain durational consistency within syllable strings. Infant syllable durations were longer and more variable than adult durations. The results from the present study were discussed in the context of the development of the motor system and were concurrent with the view that rhythmic behaviors in infancy represent a stage during the transition towards voluntary coordinated motor movements