Information Structure and Sentence Form

Why do languages have so many different ways of expressing the same idea? Lambrecht addresses this question through an investigation of the "information structure" of sentences. His analysis is based on the observation that the structure of a sentence reflects a speaker's assumptions about the hearer's state of knowledge and consciousness at the time of the utterance. Four independent but interrelated categories are analyzed: presupposition and assertion, identifiability and activation, topic, and focus.