Automatic segmentation, recognition of phonetic units and training in the KEAL speech recognition system

This paper describes the acoustic-phonetic recognizer which performs the early stages of analysis in the KEAL system. The objective of this module is to transform the continuous speech signal representing the uttered sentence into a string of lower units. Four main linguistic units have been considered : phones, phonemes, syllables and words. The KEAL acoustic-phonetic recognizer consists of components for carrying out three main tasks : acoustic analysis, labelling and training. Syllabic segmentation accuracy of 95%, an average phonemic recognition rate of 61% and a word recognition accuracy of 93% are obtained using 26 phonemic classes, isolated words (digits and operators : +,-,*,...) and continuous speech which different speakers. Preliminary results on number recognition (each number being composed of several digits spoken without insertion of pauses) give an accuracy of 90% after speaker adaptation.