The developing of prosody in infants: a longitudinal study over the first 16 months of infant life

Background The acquisition and development of prosodic aspects of vocal intonation are of special interest within the larger context of language acquisition. Method The present study explored the developmental trajectories of infant prosodic abilities from 4 to 16 months of life with an intensive time points assessment. Several aspects were considered: an acoustic analysis of infant vocal productions with specific software, the analyses of all the prosodic variables associated with the fundamental frequency (F0 mean, F0 range, and F0 final contours), the individual variability and the complexity of the vocal productions of the infants. Results The multi-level analysis evidenced specific prosodic developmental trajectories that differ for the different kind of vocal productions since the first months of life. Conclusions The findings suggest that in the second half of the first year of life infants show an intonational repertoire that may help manage interactions with their caregiver and that individual variability has to be taken in consideration when assessing infants’ prosody.