A Formal Model of Systemic Grammar

Abstract

Despite the fact that systemic grammar (see Halliday, 1973, 1978; Winograd, 1983, chapter 6) has a relatively long history, and has been adopted in several computer implementations (Davey, 1978; Mann & Matthiessen, 1983), it has never been rigorously formalised in the way that traditional grammars have. The reason for this appears to be that the formal tools applied to traditional structural grammars are not so easily applied to a functional theory. In addition, it seems that the ‘rigorous rules’ used to formalise traditional grammars are viewed by systemic linguists as inherently structural (e.g. Halliday, 1978, pp. 191–192). The formal model of systemic grammar presented here will involve ‘rigorous rules’ but will not compromise the functional perspective of language as a ‘resource’. This formalisation will allow us to define such notions as the language generated by a grammar, and to demonstrate results relating to properties of two algorithms for producing text from a grammar. The central issues discussed include the correctness and efficiency of these generation processes.