1. A method for performing recognition of speech in reply to a prompt, the method comprising: storing a data set, in a dialog manager module, the data set including a plurality of information items and a corresponding set of one or more improbable values for each of the plurality of information items, the one or more improbable values for each of the plurality of information items comprising one or more values that are not valid for the information item based on a context of the prompt; receiving a plurality of recognized ordered interpretations from an automatic speech recognition (ASR) engine, the plurality of recognized ordered interpretations each including a plurality of received information items; and comparing a value of one of the plurality of received information items for a first recognized ordered interpretation to the data set to determine if the value of the one of the received information items matches any of the set of one or more improbable values for the information item.
8. The method of claim 1 , wherein the one or more improbable values for each of the plurality of information items comprise one or more values that are incongruous with the information item.