Logic and the comprehension of language

This thesis examines what is necessary to formally model a hearer's comprehension of a natural language sentence. Our theory of comprehension should at least explain how different words within the same grammatical class make different contributions to the meaning of a sentence. And, our theory should explain how the ``full propositional form'' that a speaker communicates is recovered from the relatively semantically underspecified acoustic signal. A model is provided which achieves this. A speaker is said to understand an utterance by, first, choosing the maximally ``relevant'' full propositional semantic enrichment of the underspecified acoustic signal, measured according to a formally defined comparison operator, and, then, computing the inferences that follow from that chosen propositional form in conjunction with their individual word-/world-knowledge. This model of comprehension apparently makes comprehension relative to an individual's idiosyncratic knowledge. So, I also discuss how conventionalized word-meanings co-ordinate individuals' knowledges to allow successful interpersonal communication.