Sociolinguists have made considerable headway in identifying and describing the relationship between mobility, linguistic resources, and forms of inequality. Despite such advances, however, we argue that it is as important as ever to continue to rethink what kinds of phenomena are analyzed, the distinctions and categories that might be imposed on the data collected, and the theoretical and methodological approaches used to pursue that inquiry. This special issue investigates how movement across borders (and over time) influences ideologies of language, experiences of language learning, and the linguistic repertoires that emerge in specific local contexts.