As it is a common practice in Dual Language Education (DLE) classrooms throughout the United States, language separation tends to be a planning policy that is usually enforced by curriculum designers, school administrators, and bilingual teachers. However, research has shown that DLE teachers and students have the potential of teaching and learning "bilingually" in their own terms. Using theoretical perspectives from Anthropolitical Linguistics coupled with Ruíz's seminal work on language as problem, resource, and right; and other socio-cultural frameworks, this paper presents an ethnographic case of a seventh-grade DLE mathematics classroom, and examines how the members of this mathematics community use their bilingual abilities in a flexible way; which in turn, influence the development of mathematics biliteracies. Drawing from a larger ethnographic project, this study shows how the members of a bilingual mathematics community of practice break language norms, which prevail in DLE classrooms, to promote mathematics biliteracies. Findings suggest that using a 'translanguaging' approach in DLE classrooms is an effective way for teaching and learning mathematics with a biliteracy approach. Some implications for schools, teachers, and teacher educators are discussed.