Embodiments of a dialog system that utilizes a multi-modal input interface for recognizing user input in human-machine interaction (HMI) systems are described. Embodiments include a component that receives user input from a plurality of different user input mechanisms (multi-modal input) and performs certain synchronization and disambiguation processes. The multi-modal input components synchronizes and integrates the information obtained from different modalities, disambiguates the input, and recovers from any errors that might be produced with respect to any of the user inputs. Such a system effectively addresses any ambiguity associated with the user input and corrects for errors in the human-machine interaction.