Integration of Utterance Verification

Methods for utterance veriication (UV) and their integration into statistical language modeling and spoken language understanding formalisms for a large vocabulary spoken understanding system are presented. The paper consists of three parts. First, a set of acoustic likelihood ratio based utterance veriication techniques are described and applied to the problem of rejecting portions of a hypothesized word string that may have been incorrectly decoded by a large vocabulary continuous speech recognizer. Second, a procedure for integrating the acoustic level conndence measures with the statistical language model is described. Finally, the eeect of integrating acoustic level conndence into the spoken language understanding unit (SLU) in a call{ type classiication task is discussed. These techniques were evaluated on utterances collected from a highly unconstrained call routing task performed over the telephone network. They have been evaluated in terms of their ability to classify utterances into a set of fteen semantic actions corresponding to call{types that are accepted by the application.