Managing lexical knowledge in LEU/2

Abstract

This article deals with the problem of incomplete lexical knowledge in natural language systems. For several reasons, it is hard or even impossible to supply NL-systems in advance with all the lexical knowledge that may become necessary in an application. For example, it is difficult to predict which words will be used in what sense by its users. More important, natural language includes word formation rules allowing the creation of new words and new word usages. The paper describes the lexical component of the fully implemented NL text understanding system LEU/2. This component, called Lexicon Manager, is able to deal with unknown nouns and adjectives using a set of interacting strategies and knowledge sources and to acquire the lexical knowledge necessary to analyze and generate natural language text. It is argued that dealing with unknown words requires the ability to extend or to refine lexical knowledge as well as conceptual knowledge.