In this chapter, we trace the development of the use of ethnicity as related to language variation. As with the other variables of class, age and so on, ethnicity used to be seen as more or less fixed and easily determined. That is, a person’s ethnicity has at times been treated as an unproblematic part of their essential nature: stable, determined and unchanging. It is true that some research shows a correlation between particular linguistic variables and ethnicity. However, we will see that it’s not always quite so straightforward. How individuals articulate their ethnicity and how it is understood may vary because of the communicative context they’re in, the people they’re interacting with as well as other parts of their identity.