In this paper, we present a computational framework for the detection of ontological discrepancies in multiagent systems. The framework is developed as a basis for the generation of feedback utterances at the ontological level. In our method, presuppositions are extracted from the sender?s message, expressed in a common vocabulary, and compared with the recipient?s ontology, which is expressed in type theory. Discrepancies are detected by the receiving agent if it notices type conflicts, particular inconsistencies or ontological gaps. Depending on the kind of discrepancy, the agent generates a particular feedback message in order to establish alignment of its private ontology with the ontology of the sender.