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Non-transformational grammar The class of non-transformational generative grammars comprises frameworks that share many of the broad goals espoused in early transformational work (e.g., Chomsky 1957) but use different devices to pursue these goals. This class of grammars can be divided into three principal subclasses. The family of feature-based approaches, also known variously as ‘unification-based’, ‘constraint-based’ or ‘description-based’ grammars, makes essential use of complex-valued features in the analysis of local and non-local dependencies. Generalised phrase-structure grammar, head-driven phrase structure grammar and lexical functional grammar are among the most important members of this class. There are two basic varieties of relational approaches – relational grammar and arc pair grammar – which both accord primacy to grammatical relations and relation-changing rules. The class of categorial approaches uses flexible category analyses and highly schematic rules to combine expressions that often do not correspond to syntactic constituents in other approaches. Categorial approaches fall into three main groups: versions of the Lambek calculus, combinatory categorial grammars and offshoots of Montague grammar. This article identifies the distinctive char-

acteristics that broadly define the three primary subclasses and summarises some significant properties and insights of individual frameworks.

Feature-based grammars