Social and environmental interactions in infant language development: a systematic review

This systematic review investigates how the interaction between infants and their environment (both physical and social) influences language development in early childhood. Following PRISMA guidelines, twenty five empirical studies examining this interaction were selected. The results highlight four main themes: (1) the importance of direct social interactions, especially those conducted by caregivers, which are more effective in word learning compared to video-mediated or virtual agent interactions; (2) the influence of caregivers' speech characteristics, with infant-directed speech (IDS) facilitating word processing and retention; (3) the quality of interactions in care and educational settings, showing that warm and responsive interactions are associated with better developmental outcomes; and (4) metalinguistic development, where children's ability to reflect on language develops alongside other linguistic skills, supported by social interactions and caregiver support. These findings underscore the crucial role of a rich environment with high-quality social interactions in infants' linguistic and cognitive development.