Abstract
This chapter explains the ways in which language, though not a diagnostic feature of autism, is nonetheless central to it. The chapter provides an overview of the language challenges in autism, including speech, vocabulary, grammar and syntax, pragmatics, language comprehension, and narrative skills. It discusses how these challenges range in severity across the autism spectrum, from individuals who are non-speaking to those who are fully fluent but still struggle with social communication. It also discusses some of the uncertainties surrounding non-speaking autism. It then surveys the various ways in which language affects social development, cognitive development, academic development, behavior, and psychological well-being.