This qualitative research study built on the existing research on young children’s composing. Although many researchers have examined the social nature of young children’s composing, there is little to no research that has focused on the social work of young bilingual children who are learning to write in two languages. This study explored the social activity of bilingual kindergarten writers in a two-way bilingual immersion program. Specifically, it examined (a) the face-to-face interactions of young bilingual writers, (b) the ways in which children’s interactions related to the written/drawn products that were being created at the writing center and during journal time and (c) the oral language that was being used as children engaged in writing activities. Data were collected for five months in a two-way immersion classroom in South Texas school district. Data sources, including expanded field notes, video recordings of students’ interactions, written/drawn artifacts and informal interviews with the students and the teacher were analyzed using the constant comparative method and microethnographic discourse analysis. Analysis revealed that bilingual children’s interactions were varied and complex. As they explored written language alongside their peers, the young writers in this study navigated through multiple peer worlds that were defined in part by the language and/or languages that were being spoken. In order to participate in these worlds the children had to draw on their entire linguistic repertoire, as well as differentiated social understandings that are unique to bilingual individuals. As children attempted to initiate interactions with their peers, they assumed the role of linguist; they made purposeful decisions about how and when they used both of their languages. Factors that influenced children’s oral language use included comfort level, peer culture and the out-of-classroom context. Also noteworthy is that these children drew on both languages to support their biliteracy learning. Both Spanish dominant children and those children who were balanced in their language use drew on their Spanish orally to support their writing in English while English dominant students tapped into their Spanish speaking capabilities to support their writing in English. / text