Method and apparatus for dynamic adaptation of a large vocabulary speech recognition system and for use of constraints from a database in a large vocabulary speech recognition system

Abstract

The vocabulary of a large-vocabulary speech recognition system is structured to effectuate the rapid and efficient edition of words to a lexical network storing the vocabulary. The lexical network is structured to include Phonetic Constraint Nodes which organize the inter-word phonetic information in the network, and Word Class Nodes which organize the syntactic/semantic information in the network. Network fragments, corresponding to phoneme pronunciations and labeled to specify permitted interconnections, are precompiled to facilitate the rapid generation of pronunciation for new words and thereby enhance the rapid addition of words to the vocabulary even during speech recognition. Different language models and different vocabularies for different portions of a discourse are invoked dependent in part on the discourse history.