My dissertation concerns the nature of linguistic understanding. A standard view about linguistic understanding is that it is a propositional knowledge state. The following is an instance of this view: given a speaker S and an expression alpha that means M, S understand alpha just in case S knows that alpha means M. I refer to this as the epistemic view of linguistic understanding. The epistemic view would appear to be a mere conceptual truth about linguistic understanding, since it is (...) entailed by the following two claims that themselves seem to be mere conceptual truths: S understands alpha iff S knows what alpha means, and---given that a means M--- S knows what alpha means iff S knows that alpha means M. I argue, however, that this is not a mere conceptual truth. Contrary to the epistemic view, propositional knowledge of the meaning of alpha is not necessary for understanding alpha. I argue that linguistic understanding does not even require belief. My positive proposal is that our understanding of language is typically realized, at least in native speakers, as a perceptual capacity. Evidence from cognitive neuropsychology suggests that our perceptual experience of language comes to us already semantically interpreted. We perceive a speaker's utterance as having content, and it is by perceiving the speaker's utterances as having the right content that we understand what the speaker says. We count as understanding language in virtue of having this capacity to understand what speakers say when they use language. This notion of perceiving an utterance as having content gets analyzed in terms of Dretske's account of representation in terms of a teleological notion of function: you perceive a speaker's utterance as having content when the utterance produces in you a perceptual state that has a certain function in your psychology. I show how this view about the nature of linguistic understanding provides an attractive account of how identity claims can be semantically informative, as opposed to merely pragmatically informative, an account that avoids the standard difficulties for Fregean views that attempt to account for the informativeness of identity claims in terms of their semantics. (shrink)