This document provides an overview of what language is from a linguistic perspective. It discusses that language is a uniquely human ability that allows for the production and understanding of strings of sounds to convey meaning. It notes that children acquire language proficiency around age 5 without explicit knowledge of the underlying rules. The document also describes linguistic knowledge regarding sound systems, words, creativity and grammar. It discusses the difference between descriptive and prescriptive grammars, as well as theories of universal grammar and language development. It considers what distinguishes human language from animal communication systems.