Proceedings of the Annual Meeting of the Cognitive Science Society

Caregiver infant-directed (ID) speech and infant vocal productions are both important for speech-language development. Although music experience is associated with language abilities at later ages, the role of music in infant language development is unclear. We used manual annotation to obtain quantities of different infant vocalization types and quantities of caregiver speech and song during 5-minute excerpts from daylong audio recordings of 3-, 6-, 9- and 18- month-olds. Excerpts in which caregivers produced more infant-directed musical vocalizations (such as singing or humming) also contained fewer speech-related infant vocalizations. This could be driven by musical input causing infants to be quieter as they attend auditorily and/or by adults singing or humming during times when infants are less vocal. We also found a negative association between non-infant- directed adult speech and infant speech-related vocalization, positive associations between quantities of infant-directed speech and infant crying and laughter, and age trends consistent with prior reports.