This document discusses the topic of sociolinguistics. It defines sociolinguistics as the study of language use in society and how language interacts with and helps shape social structures. The document outlines three subcategories of sociolinguistic study: micro-sociolinguistics, macro-sociolinguistics, and three areas of sociolinguistic research - language variation, language contact, and linguistic relativity. It provides examples of research within these areas and discusses implications for language teaching.