This document discusses social variations in language use. It explains that George Yule focuses on how language varies based on education level and socioeconomic status. Sociolinguistics studies the relationship between language and society. The document outlines differences in language between middle and working class individuals as well as between those with more or less education. Features like pronunciation, vocabulary, and grammar patterns can serve as social markers of one's background. Style and code-switching between formal and informal registers also vary depending on social context.