Syntax is the component of grammar that governs how words are arranged into phrases and sentences. It is the system that allows speakers to produce and understand an unlimited number of novel sentences from a finite set of words and rules — what Noam Chomsky called the "infinite use of finite means." Understanding syntax is central to understanding how language is processed, acquired, and represented in the brain.
Phrase Structure
Sentences are not just strings of words but hierarchically organized structures. "The old man saw the young woman with binoculars" has multiple possible structures (who has the binoculars?) determined by how phrases are grouped. Phrase structure rules describe how words combine into phrases (noun phrases, verb phrases, prepositional phrases) and how phrases combine into sentences. This hierarchical structure is fundamental to meaning: "The dog bit the man" and "The man bit the dog" contain the same words but have different structures and different meanings.
Chomsky's Contributions
Chomsky's transformational grammar (1957) proposed that sentences have a deep structure (underlying meaning) and a surface structure (actual word order), connected by transformational rules. This explained how "The dog chased the cat" and "The cat was chased by the dog" share meaning despite different word orders. Chomsky's subsequent work developed through several theoretical frameworks (Government and Binding, Minimalism), all maintaining the core idea that language involves abstract structural principles.
A defining property of human syntax is recursion — the ability to embed structures within structures of the same type indefinitely. "The rat that the cat that the dog chased caught escaped" embeds clauses within clauses. While deeply embedded structures become difficult to process (due to working memory limitations), the grammatical capacity for recursion may be a uniquely human linguistic ability. Hauser, Chomsky, and Fitch (2002) controversially proposed that recursion is the only uniquely human component of language.