Bilingual Language Input to Infants in Bolivia and the United States.

Characterizing dual language input in children's environments is critical to understand how early language experiences influence bilingual language development. However, little is known about how dual language exposure is distributed across factors known to influence the kinds of input children receive. This study examined how infants' exposure to each of their languages is distributed across different speakers (adults vs. other children) and speech registers (child- versus adult-directed speech). We examined daylong audio recordings of infants' language environments in two bilingual communities: an indigenous Quechua- and Spanish-speaking community in Bolivia (n = 10, age = 5.7-23.4 months, five females, five males) and an immigrant Spanish- and English-speaking community in the United States (n = 10, age = 6.4-12.6, four females, six males). Infants in both communities were more likely to hear the societal language from older children than from adult caregivers. Infants were also more likely to hear the societal language in child-directed speech, and more of the minoritized language in adult-directed speech, by a factor of more than 4 to 1. These findings shed light on how bilingual infants' language exposure is distributed across social contexts, which may have implications for bilingual language development and maintenance, as distinct social contexts afford different opportunities for engagement and interaction over the course of learning two languages in infancy.