The Context Change Potential of Questions and their Foci

The semantic and pragmatic effect of inerrogative illocutionary operator is analyzed in a dynamic setting in the framework of structured meaning representation with respect to the dialogue participants' shared common ground. I propose a framework for an optinal interpretation of focus phrases in terrogatives share the essential properties of focus in general, namely that they introduce alternatives to be taken advantage of by relevant focus-sensitive operators. The theory makes an interesting prediction on the distribution and interpretation of double questions in which one question gets modified by another. A further extention of the theory is spelled out to account for other non-assertional illocutionary operators like imperatives and their foci.