Social and Community Influences on Language Switching in Bilingual Toddlers’ Everyday Input

Language switching is a central feature of bilingual toddlers’ input, yet the everyday patterns that infants experience remain poorly understood. To characterize the switching that bilingual toddlers’ encounter, we recorded naturalistic play interactions on two occasions: a dyadic session between the toddler and a primary caregiver and a multi-person session that included additional household members. We calculated the number of language switches per minute produced by speakers in toddlers’ environments and classified these switches as within-speaker (a single person alternating languages) or across-speaker (different speakers using different languages in sequence). Patterns of language switching were then compared across Spanish-English (New Jersey) and French-English (Montreal) bilingual communities. Compared to sessions with only a primary caregiver, toddlers heard approximately 50% more speech and twice as much language switching in sessions with multiple household members present. This shift in switching was primarily driven by increased across-speaker switches, a pattern that was especially pronounced in the French-English community. Although there was considerable variability in switching across families, primary caregivers showed relatively stable switching behavior across sessions, suggesting that they may provide a source of consistency within otherwise dynamic language environments. Together, these findings underscore the importance of recognizing that language learning unfolds within interpersonal contexts, and that variation in social configurations may be particularly consequential for bilingual learners’ language input.