Languages are often taken to be natural entities with clearly defined borders. However, anthropological and sociolinguistic work on multilingualism shows this apparent fact is up for debate. What is the difference between a dialect and a language? Do different styles of speaking count as codeswitching? How do ideologies about multilingualism shape face-to-face interaction and state language policy? This introductory course will explore these questions and more, drawing on a wide variety of cultural contexts and communicative settings.