This volume brings together researchers in conversation analysis who examine the practice of alternating between English and German, Italian, Spanish, Swedish and Vietnamese in the classroom. The collection shows that language alternation is integral to being and learning to become a bilingual, and that being and learning to become a bilingual are accomplished through a remarkably common set of interactional objects and actions, whose sequential organisations are quite similar across languages and educational sectors. This volume therefore shows that having recourse to more than one shared language provides an important resource for getting the work of language learning and teaching done through an orderliness that can be described and evaluated. The findings and the suggested pedagogical applications described in the volume will be of significant interest to researchers and teachers in a range of fields including second and foreign language teaching and learning, conversation analysis, teacher education and bilingualism.