Semantics and Speech Understanding

Syntactic constraints and expectations are based on the patterns formed by a given set of linguistic objects, e.g. nouns, verbs, adjectives, etc. Pragmatic ones arise from notions of conversational structure and the types of linguistic behavior appropriate to a given situation. The bases for semantic constraints and expectations are an a priori sense of what can be meaningful and the ways in which meaningful concepts can be realized in actual language. The paper describes how semantics is being used in several recent speech understanding systems. It then expands the generalities of the first section with a detailed discussion of some actual problems that have arisen in the attempt to understand speech.