A growing body of research recognizes the pervasive difficulties involved in accommodating multilingual practices in the English language classroom and acknowledges that one aspect of this conundrum is the role that languages play in the constitution of student identities. Such studies point to how students use off-stage spaces to covertly engage identities that are devalued in on-stage classroom interaction that comes under the teacher's authority. In this article, we examine data on Singapore English classrooms at the secondary school level. By analyzing interactions in both off- and on-stage spaces, we discuss how the work that students do in constructing identities can be integrated into the linguistic mediation of learning. We do this by offering an interpretation of Rampton's notion of "crossing," emphasizing how this concept promises to link theoretical analysis and practical classroom pedagogy in a socioculturally sensitive way, one that considers the Singaporean multilingual situation and the importance of languages for identity work. (Contains 10 footnotes.)