Patent ID: 7124085

Claim:
A constraint-based speech recognition system for use with a form-filling application employed over a telephone system, the system comprising: an input signal comprising: a) speech input, and b) non-speech input of a type generated by a user via a manually operated device; a constraint module operable to: a) access an information database containing information suitable for use with speech recognition, wherein the information database is a hierarchical data structure of short lists of speech recognition candidates, the shortlists being hierarchically arranged according to pre-defined classes that can be entered via the non-speech input, and b) generate candidate information based on the non-speech input and the information database, the candidate information corresponding to a portion of the information, wherein said constraint module requires entry by a user of only so many classes via the non-speech input as required to provide sufficient constraint for speech recognition in accordance with at least one of: (a) a maximum amount of the candidate information; or (b) a maximum measure of confusability between candidates of the candidate information; and a speech recognition module operable to recognize speech based on the speech input and the candidate information.