Chapter 2 discusses the questions ‘what is language’ and ‘what is a language’. We explore properties of standard national languages as compared to regional dialects, registers, and pidgin and creole varieties. This survey illustrates that language seen as an abstract ability underlies all forms of linguistic variation and that the same sorts of grammatical concepts underlie any variety while questions of prestige or standard usage are fundamentally social and cultural issues. The interaction of social, cultural and linguistic issues is discussed from the perspective of language education.