The Role of Caregiver Linguistic Input in Infant Joint Attention and Early Language Development: A Longitudinal Study

This study investigated the relationships among infants' attention-following (AF) abilities, caregiver linguistic input, and early language development. Using longitudinal data from home observations (6–9 months) and structured lab assessments (9–12 months), we found that AF performance at 9–12 months was significantly correlated with receptive and expressive language scores at 12 months, though these associations weakened by 18 and 22 months. Caregiver attention-directing utterances were positively associated with both 6-month AF performance and 12-month language outcomes, although their frequency declined from 6 to 9 months, suggesting caregivers adjust their strategies as infants' AF skills develop. Although moderation analyzes did not reach statistical significance, trends indicate that higher levels of caregiver attention-directing speech might enhance the relationship between AF and language outcomes. These findings highlight the dynamic role of caregiver linguistic input in shaping infants' early attention sharing and language development. The results also inform intervention approaches for infants at risk for language delays.