In generative grammar, non-configurational languages are languages characterized by a non-rigid phrase structure, which allows syntactically discontinuous expressions, and a relatively free word order. In configurational languages in contrast, the subject of a sentence is outside the finite verb phrase (VP) (directly under S below) but the object is inside it. Since there is no VP constituent in non-configurational languages, there is no structural difference between subject and object. The distinction (configurational vs. non-configurational) can exist in phrase structure grammars only. In a dependency-based grammar, the distinction is meaningless because dependency-based structures do not acknowledge a finite VP constituent.
The concept of non-configurationality was developed by grammarians working within Noam Chomsky's generative framework. Some of these linguists observed that the Syntactic Universals proposed by Chomsky and which required a rigid phrase structure was challenged by the syntax of some of the world's languages that had a much less rigid syntax than that of the languages on which Chomsky had based his studies. The concept was invented by Ken Hale who described the syntax of Warlpiri as being non-configurational. However the first to publish a description of non-configurationality was Chomsky himself in his 1981 lectures on Government and Binding, in which he referred to an unpublished paper by Hale. Chomsky made it a goal of the Government and Binding framework to accommodate languages such as Japanese and Warlpiri that apparently did not conform to his proposed language universal of Move α. Hale later published his own description of non-configurationality in Warlpiri. Katalin Kiss developed the concept of Discourse Configurationality to describe languages where constituent order is primarily determined by pragmatic factors.