Grammaticality

Grammaticality is a status of a sentence or utterance relative to a given language's grammar, indicating whether it conforms to the accepted structural rules, word order, morphophonology, and agreement patterns of that language. In linguistics, grammaticality is typically evaluated by native speakers through judgments of acceptability, with the idea that well-formed sentences align with the speaker community's grammatical knowledge (competence) rather than with actual usage in every instance (performance).

Although often conflated with acceptability, grammaticality denotes the formal constraints of a grammar. A sentence may be grammatical but pragmatically odd or semantically anomalous, as in "Colorless green ideas sleep furiously" which follows syntax and morphology but lacks plausible semantics. Conversely, a sentence can be ungrammatical, violating morphological agreement or allowable structures, such as "She walk to the store" in Standard English.

Descriptive linguistics adopts grammaticality as the property of sentences that fit a language's rules, while prescriptive approaches label certain constructions as correct or incorrect. Researchers study grammaticality through acceptability judgments, corpus data, and language processing experiments. Grammaticality also interacts with dialect, register, and cross-linguistic variation; what is grammatical in one language or dialect may be ungrammatical in another.

The concept underpins theories of syntax, such as phrase structure and long-distance dependencies, and helps distinguish competence from performance. It remains a central, though debated, notion in formal linguistics, cognitive science, and language pedagogy.