This study starts from the premise that academic mobility contributes to the development of students' plurilingual identities and that study abroad contexts aiming at becoming global spaces are particularly interesting sites to explore the individuals' discursive work to (re-)construct their plurilingual identities by reconciling their language ideology with specific practical and institutional constraints. Two focus-group discussions with students from a Catalan/Spanish bilingual institution selected to take part in an Erasmus exchange in a Danish university, and one with academic and administrative staff of this host university, have been analysed using Membership Categorisation Analysis. The analysis reveals the discursive "methods" that students and staff, as plurilingual speakers whose repertoire includes a lesser-spoken language such as Danish and Catalan, display in order to "make sense" of their language choice, which places the local (Danish) language in a clearly subsidiary position in the life of the university.