Representation Issues in Systemic Functional Grammar and Systemic Grammar and Functional Unification Grammar

摘要

Nigel is a large diverse computational grammar for text generation. Its framework is an implementation of Systemic Functional Theory of grammar and it constitutes a context in which the representation of systemic theory can be explored and studied. This paper surveys the representational devices used in the Nigel grammar and the representational issues that they raise in relation to systemic theory. These issues are diagnosed in the light of the metafunctional differentiation of systemic theory. Systemic Functional Grammar (SFG) and Functional Unification Grammar (FUG) are superficially very different approaches to grammatical knowledge, but they share an underlying comparibility that runs very deep. FUG shares with systemic descriptions an emphasis on the functions of linguistic objects, and an explicit representation of feature choices. This paper explores how a systemic grammar can be represented in FUG notation, as a step toward creating a grammatical analysis program for English. Because FUG has been developed as a computational tool, expressing a systemic grammar in FUG notation allows new computational techniques to be applied to it. Among other benefits, this program will make it possible to study how much the grammatical functions of sentences are recoverable from them. It will also provide a method to test the amount of ambiguity implicit in a systemic description, a topic which has so far been inaccessible. This use of FUG as an alternate representation for SFG may have some additional benefits for both frameworks. It provides some solutions to problems in systemic notation which are described by Matthiessen. Several extensions to the FUG framework are also suggested by this study.