The course considers the challenges that language variation poses for language teaching. It is specially designed for future professionals in language learning and teaching, and offers suggestions and support for pro gradu research in this area, but it is useful for any students interested in language variation. The course reviews some of the many dimensions along which a language can vary, such as mode and register (spoken and written language, formal and informal styles), domain (special languages), social class, gender (men's and women's language) and geographical region (Englishes), and the ways in which these dimensions are and can be taken into account in the classroom. The course includes lectures and discussions of different dimensions of language variation, background reading, and a small-scale project and its written report.