A real-time phrase recognizer using telephone bandwidth speech

A system for the recognition of spoken phrases is described. The input speech is filtered to 3.3 KHz (approximating telephone bandwidth), and parameters are computed while the utterance is spoken. The remaining time necessary to produce a result is generally less than the duration of the input utterance. The recognizer assumes that the input utterance contains one of a known set of key phrases; the phrase is allowed to be included within a more or less arbitrary carrier sentence. Analysis is performed on a syllable-by-syllable basis with only the strong syllables considered in the recognition process. An interactive training facility allows flexible composition of key phrase sets. Testing has been performed for a few phrase sets, each containing less than twenty phrases. Talkers used in the training and talkers not used in the training tested the system. The phrase recognition accuracy was 92% for each group of talkers. The recognizer has been used successfully to retrieve messages from a remote computer by voice.