Prosodic input and children's word learning in infant- and adult-directed speech

This study examines (1) whether infant-directed speech (IDS) facilitates children's word learning compared to adult-directed speech (ADS); and (2) the link between the prosody of IDS in word-learning contexts and children's word learning from ADS and IDS. Twenty-four Dutch mother-child dyads participated when children were 18 and 24 months old. We collect mothers’ ADS and IDS at both ages and test children's word learning from ADS and IDS at 24 months. We find that Dutch 24-month-old children could reliably learn novel words from both ADS and IDS, and IDS had a facilitative effect. In addition, children's word learning from IDS (but not ADS) is predicted by IDS pitch range when mothers introduce unfamiliar words to children at 18 months. Our findings contribute to an understanding of the role of IDS prosody in language development, highlighting both individual differences and contextual differences in IDS prosody.