A new method for automatic generation of speaker-dependent phonological rules

This paper presents a new method for automatic generation of speaker-dependent phonological rules in order to decrease recognition errors caused by pronunciation variability. The proposed method generates phonological rules by using objective speaker's continuous speech and corresponding standard pronunciation, resulting in forming a multiple-pronunciation dictionary from a single-pronunciation dictionary. The method makes it possible to generate automatically speaker-dependent and recognizer-dependent phonological rules, and be applied to both a top-down recognizer and a bottom-up recognizer, while conventional methods are based on hand-derived general phonological rules such as coarticulation knowledge or are applied only to a bottom-up recognizer. Phrase recognition experiments with concatenated phoneme HMMs showed that the generated rules can decrease recognition errors and play a role of speaker adaptation at the phonological level.