Identifying chains in spoken Academic English

John Sinclair (1991: 109-110) proffers two models for the interpretation of language:a) the open-choice model, in which the production of language is seen to be a piece-by-piece construction of phrases and larger syntactic entities. The most typical realisation of this approach is the tree-diagram, at each step, represented by the nodes, a large number of choices may be made, and "the only restraint is grammaticalness". Sinclair describes this as being the usual approach adopted by grammars at the time the wark was written;b) the idiom principle, described as follows [...].When evaluating the relative importance of the two models, Sinclair states that neither are sufficient on their own to describe language, and especially spontaneous oral production. To the contrary, both play a fundamental role, however, the second should be adopted as default, the first is to be resorted to only in those cases whereby a phenomenon cannot be explained by the idiom principle.