Introduction

The lexicon has come to occupy an increasingly central place in a variety of current linguistic theories, and it is equally important to work in natural language processing. The lexicon – the repository of information about words – has often proved to be a bottleneck in the design of large-scale natural language systems, given the tremendous number of words in the English language, coupled with the constant coinage of new words and shifts in the meanings of existing words. For this reason, there has been growing interest recently in building large-scale lexical knowledge bases automatically, or even semi-automatically, taking various on-line resources such as machine readable dictionaries (MRDs) and text corpora as a starting point, for instance, see the papers in Boguraev and Briscoe (1989) and Zernik (1989a). This chapter looks at the task of creating a lexicon from a different perspective, reviewing some of the advances in the understanding of the organization of the lexicon that have emerged from recent work in linguistics and sketching how the results of this work may be used in the design and creation of large-scale lexical knowledge bases that can serve a variety of needs, including those of natural language front ends, machine translation, speech recognition and synthesis, and lexicographers' and translators' workstations.

Although in principle on-line resources such as MRDs and text corpora would seem to provide a wealth of valuable linguistic information that could serve as a foundation for developing a lexical knowledge base, in practice it is often difficult to take full advantage of the information these existing resources contain.