New Developments in Lexical Functional Grammar

This article provides a brief introduction to a number of key advances in LFG since the late 1980s. A description of the framework itself is given in Neidle (this volume), which provides an overview of the 1982 version of the theory, together with a sketch of a major subsequent development, Lexical Mapping Theory. LFG as a framework for linguistic description has its roots in the desire to elaborate a fully explicit, mathematically precise and computationally oriented model of linguistic structures which would support a psychologically plausible model of human linguistic processing. Since that time, LFG has been applied to the description of a wide variety of diierent languages, and has enjoyed a signiicant degree of innuence in computational linguistics. A very striking aspect of LFG is its stability as a framework. The fundamental architecture of the theory has remained constant since the late 1970s. A very important facet of LFG syntax, which signals it out from many other syntactic theories, is the representation of diierent dimensions of the syntax (c-structure and f-structure, or external and internal syntax) by means of diierent formal entities: the architecture combines a context free grammar formalism (for c-structure) with attribute value structures (for f-structures). These (and other) diierent dimensions are related by structural correpondence functions, or projections, the most familiar of which is the function mapping c-structure nodes into f-structure,. As the theory has progressed, light has been cast on the nature of other structures and work has proceeded on the mapping functions. This brief review, which focusses on LFG syntax, touches on the nature of one dimension (in addition to f-structure and c-structure), namely argument structure, and the argument structure to f-structure projection. In section 1 we discuss recent work in Lexical Mapping Theory, which concerns both the nature of argument structure and the mapping from argument structure of f-structure. Much other work in LFG has been concerned with extending the description languages of LFG (for c-structure and f-structure), and on the c to f-structure projection. The rest of this review of recent development focusses on this, and on the range of syntactic analyses made available in the LFG architecture. We pick out for particular attention three aspects of this work: that on principles of c-structure organisation and the mapping to f-structure; that on the extension of the f-structure description language to include functional uncertainty equations and some linguistic analyses which exploit this; and …