Cognitive grammar is a cognitive approach to language developed by Ronald Langacker, which considers the basic units of language to be symbols or conventional pairings of a semantic structure with a phonological label. Grammar consists of constraints on how these units can be combined to generate larger phrases which are also a pairing of semantics and phonology. The semantic aspects are modeled as image schemas rather than propositions, and because of the tight binding with the label, each can invoke the other.
Langacker develops the central ideas of cognitive grammar in his seminal, two-volume Foundations of cognitive grammar, which became a major departure point for the emerging field of Cognitive Linguistics.
Like construction grammar (developed by Langacker's student Adele Goldberg), and unlike many mainstream linguistic theories, cognitive grammar extends the notion of symbolic units to the grammar of languages. Langacker further assumes that linguistic structures are motivated by general cognitive processes. In formulating his theory, he makes extensive use of principles of gestalt psychology and draws analogies between linguistic structure and aspects of visual perception.