Recent research has shown that children raised bilingually use two languages appropriately from an early age without confusion (Genesee 2001) and that bilingual development mirrors that of monolinguals if both languages are accounted for (Holowka et al. 2002). Such research primarily has focused on the cognitive domain of dual language acquisition, leaving open questions about the role of social factors in development. Extensive work on language socialization in the monolingual setting (Heath 1983, Nino and Snow 1996, Ochs and Schieffelin 1986, 1995), and recent investigations with bilinguals (Schecter and Bayley 2003; Toohey 2005) has shown that the sociolinguistic environment influences both the developmental trajectory and the acquisition of grammatical structures. Yet, research rarely has accounted for the child's own agency in the process of being inculcated into language as a cultural practice. The dearth of such research has meant that many of the complex ways in which cognition and socialization might specifically feed development have been left unexplored. Drawing from a three-year ethnographic study of two French-English bilinguals acquiring French in a minority language setting and bilingual corpuses from the CHILDES database, this dissertation examines the multifacted nature of child language acquisition from both cognitive and social perspectives. I posit that language acquisition is a dialogic process occurring at the intersection of cognition, input, and socialization. The first section of this study investigates the formal linguistic level, bringing new data from the children's nonce borrowing, cross-linguistic overgeneralizations, and code switching showing that these bilinguals extract cross-linguistic principles in order to feed development, while they nonetheless develop two distinct linguistic systems. The data demonstrate that these particular children show signs of acceleration in some structures, delay in other structures, and an ability to transfer cross-linguistic knowledge. The second part of this study, cast in a poststructuralist framework with a special focus on adult-child and sibling interactions, explores how competing discourses (the children's community, schools, home) and language input interact with the children's own agency. It is shown that the interaction between the cultural and cognitive domains provides social and linguistic materials for building both bilingual-bicultural identities and two distinct linguistic systems.