LINGUISTIC TOOLS FOR SPEECH RECOGNITION AND UNDERSTANDING

A realistic model of speech recognition and understanding should be heavily based both on linguistic and acoustic knowledge. If this fact seems to be acknowledged by most research people in the field it is not yet clear how to thread that knowledge into acoustic evidence. We present a proposal that tries to solve some of the problems involved in this task. In particular, acoustic patterns made up of word models are substituted by a model which makes use of features and syllables. The phone ( the phoneme is too abstract!) and the word are regarded as abstract objects which are built up the former from feature matrices, and the latter from syllables and morphological parsing into morphemes. Thus the lexicon is not a list of word forms but is composed of root morphemes and affixes in graph structure, and is traversed by a parser which makes use of rules for the composition of legal words of the language from subword units. Hypotheses are fired out both at phone and at syllable level on the basis of feature extraction.