Recently, the incorporation of students' home languages into monolingual classrooms has been reinvigorated by a scholarly focus on extended linguistic repertoire. In bilingual programs, ideas of language separation have traditionally influenced teaching and learning as a way to protect the minority language, but there is a growing call to engage with the complexity of students' language practices. In this article, it is suggested that the English-medium (dominant language) classroom can be an effective site for exploring how to leverage and affirm students' home language practices in bilingual education, and also to support the minority language in the program. Data are drawn from a design-based study that investigated the transition of a Japanese-English primary bilingual program from 30% of instruction in Japanese to a 50:50 program. As part of the study, a Foundation teacher and a Year 5/6 teacher worked towards English curriculum objectives by incorporating languages their students spoke at home, including Japanese, into the English-medium classes. Findings revealed that some Foundation students did not immediately draw on home language practices, instead choosing to use Japanese, whereas the Year 5/6 students demonstrated ambivalence towards Japanese but not towards other language practices.