This document discusses language variation between social classes. It provides examples of Cockney English and Black English that show differences in pronunciation patterns between social groups. It also summarizes research by William Labov on language usage in New York City that found people from higher social classes pronounced /r/ sounds more strongly. Finally, it mentions Alan S.C. Ross's terms "U English" and "non-U English" that referred to vocabulary differences between social classes in 1950s Britain. In conclusion, it states that while language variation exists between social classes, these differences are arbitrary and rules of language use vary across groups.