His research combines formal tools and experimental methods from linguistics and other areas of cognitive science to work toward a unified theory of language understanding as a cognitive phenomenon. He has worked on a variety of topics such as the semantics of modals and degree expressions, the pragmatics of vagueness and presupposition, inductive vs. deductive reasoning, and models of various pragmatic phenomena which treat language understanding as a problem of Bayesian inference. He has argued in various domains that combining logical and probabilistic models not only achieves a desirable theoretical unification but also improved empirical coverage and new theoretical insights.