This chapter examines the case of less commonly studied language pairs, defined as first language/second language pairings that do not include English. Key concepts are discussed and connected to three relevant, critical issues: common learning paths, crosslinguistic influence, and multilingualism. This chapter also includes a scoping review of research on second language variation in order to assess the degree to which language pairings that do not involve English as a first or second language have been investigated. Following review of current contributions on this topic, several recommendations for practice and areas for future research are outlined.