This paper gives an account of the differences between polar and alternative questions, as well as an account of the division of labor between compositional semantics and pragmatics in interpreting these types of questions. Alternative questions involve a strong exhaustivity presupposition for the mentioned alternatives. We derive this compositionally from the meaning of the final falling tone and its interaction with the pragmatics of questioning in discourse. Alternative questions are exhaustive in two ways: they exhaust the space of epistemic possibilities, (...) as well as the space of discourse possibilities (the Question Under Discussion). In contrast, we propose that polar questions are the opposite: they present just one alternative that is necessarily non-exhaustive. The account explains a range of response patterns to alternative and polar questions, as well as differences and similarities between the two types of questions. (shrink)