Interactive speech recognition apparatus

Abstract

A speech recognition system which can perform multiple recognition passes on each word. If the recognizer is correct in its first pass, the operator may abort later passes by either pressing a key or speaking the next word. Otherwise, the operator may either wait for a second recognition pass to be performed against a larger vocabulary, or may specify one or more initial letters causing the second recognition pass to be performed against a vocabulary substantially restricted to words starting with those initial letters. Each time the user adds an additional letter to the initial string, any previous recognition is aborted and the re-recognition process is started anew with the new string. If the user types a control character after the initial string, then the string itself is used as the output of the recognizer. In one embodiment, a language model limits a relatively small vocabulary used in the first pass to the words most likely to occur given the language context of the dictated word. The system may also be used as an interactive transcription system for prerecorded speech and can operate on either discrete utterances or continuous speech. When used with prerecorded speech, the system displays the best scoring words of a recognition to the user, and, when the user choses a desired word from such a display, the system employs the portion of prerecorded speech matched against the chosen word to help determine where in that prerecorded speech the system should look for the next word to recognize.