Mother-child and father-child "serve and return" interactions at 9 months: Associations with children's language skills at 18 and 24 months.

Infants learn language through the back-and-forth interactions with their parents where they "serve" by uttering sounds, gesturing, or looking and parents "return" in prompt (i.e., close in time) and meaningful (i.e., semantically relevant to the object of interest) ways. In a sample of 9-month-old infants (n = 148) and their mothers and fathers (n = 296 parents) from ethnically and socioeconomically diverse backgrounds, we examined the associations between "serve and return" (SR) parent-child interactions and children's language skills at 18 and 24 months. We also examined the moderation effects between maternal and paternal SR interactions on language outcomes. SR interactions were transcribed and coded from videotaped parent-child toy play activities during home visits. We report three findings. First, mothers who provided more meaningful responses to their child's serves at 9 months had children with higher expressive language scores at 18 months. Second, fathers' prompt responses (i.e., within 3 s) at 9 months were associated with higher receptive language scores at 18 months, but their meaningful responses were negatively associated with receptive language scores at 24 months. Third, the negative association between fathers' meaningful responses and children's receptive language scores was reduced (compensated) when mothers' meaningful responses were high. Findings show that infants in ethnically and socioeconomically diverse families engage in frequent SR interactions with both mothers and fathers, who make unique contributions to infants' language development. We discuss implications for programs and policies that aim to promote early language development and reduce gaps in school readiness.