Vocal Development of 9-Month-Old Babies With Cleft Palate

TLDR

Babies with cleft palate often experience delayed babbling, and this study explores possible explanations for that delay. The study compared prelinguistic vocal development in 9‑month‑old babies with unrepaired cleft palate to age‑matched peers. Spontaneous vocalizations were recorded during caregiver play and the groups were compared on canonical babbling ratios, stage attainment, syllable and segmental aspects, and vocal frequency. Babies with cleft palate showed lower canonical babbling ratios and only 57 % reached the canonical babbling stage by 9 months versus 93 % of peers, had smaller consonant inventories with fewer stops, glides, and velars, more glottals, yet produced a similar number of vocalizations and had comparable syllable types.

Abstract

This study compared the prelinguistic vocal development of 9-month-old babies with unrepaired cleft palate ( n =30) and age-matched peers ( n =15). Samples of the babies' spontaneous vocalizations were obtained while they interacted with their primary caregiver during play. The groups were compared on a number of variables including (a) canonical babbling ratios, (b) percentage of babies who reached the canonical babbling stage by 9 months, (c) syllable and segmental aspects of babbling, and (d) vocal frequency. Results indicated that the babies with cleft palate had smaller canonical babbling ratios than their age-matched peers, with just 57% of the babies with cleft palate reaching the canonical babbling stage by 9 months compared to 93% of the noncleft babies. Although syllable types and length were similar for the two groups, differences were noted for consonant characteristics. The babies with cleft palate had smaller consonant inventories, with fewer stops, glides, and velars noted. Glottals occurred more frequently in the vocalizations of the babies with cleft palate. Finally, no statisti-cally significant difference was noted in the number of vocalizations produced by the two groups. Some possible explanations for why babies with cleft palate are delayed in babbling are explored.