This highly accessible introduction explores the core systems and subsystems of the languages of mainland Southeast Asia, applying the main concepts of language typology, phonology, morphology, syntax, sociolinguistics, language variation, and language contact, to this diverse language area. Written by a leading expert in the languages of this region, N. J. Enfield draws upon nearly a thousand data examples from over a hundred languages from Cambodia, China, Laos, Malaysia, Myanmar, Thailand, and Vietnam to show the many ways in which these languages resemble each other, and differ from each other, in the context of what is known globally about the diversity of human language. The book highlights the diversity of the area's languages, with a special emphasis on the minority languages, which outnumber the national languages by nearly a hundred to one. The result is a welcome corrective to widespread beliefs about the nature of a 'typical' Southeast Asian language.