While the label ‘English-medium instruction’ (EMI) seems to stand for a monolingual reality, it is common knowledge that the unabated popularity of EMI rests on the unwavering endeavour of higher educational institutions to attract international students in ever-increasing numbers. As such student cohorts come with culturally and linguistically diverse backgrounds, the classroom reality of EMI is a multilingual one, with English being the preselected lingua franca for all. With the aim to provide a detailed micro-level analysis of EMI classroom interaction, this chapter argues for a research approach that combines translanguaging and code-switching when investigating multilingual classroom practices.

When empirically applied to a highly international EMI setting in Vienna, Austria (Smit 2010), the multilingual practices of the international student group reveal different patterns of code choice contingent on activity type (side versus main talk) and communicative function. Thanks to the longitudinal nature of the classroom corpus in focus (consisting of 44 lessons spread over three semesters), the findings complement extant EMI research by foregrounding the dynamic development of a classroom community’s shared ELF repertoire by integrating some local linguistic features, thereby also indexing their growing group identity.