Background: In schools, a major obstacle to drawing on emergent bilingual students' knowledge and skills in their first language is a widespread lack of awareness about language use among adolescent English learners, including how peer talk can connect knowledge and abilities in both languages to school-based learning. Although research often acknowledges the importance of engaging students' home language and culture to bridge to academic literacies in English, few have explicitly examined bilingual peer talk as a resource for language learning during adolescence. Purpose: This study explores how emergent bilinguals engaged multiple linguistic codes to scaffold their own academic language development with peer support. Research Design: Ethnography and discourse analysis of student interactions were used to contextualize and analyze the academic language use of four Spanish-speaking adolescent immigrant students, taking into account the affordances of classroom discourse structures and peer talk. Conclusions: The study describes the linguistic resources available to Spanish-speaking adolescent immigrant students through their peers and shows that emergent bilingual youth used academic language in both Spanish and English most frequently--and in more elaborated interactions--while off-task or in less supervised spaces. Classroom discourse structures often limited student participation, particularly when students used nonstandard linguistic codes.