Detection of nasalized vowels in American English

This study is concerned with the quantification of acoustic measures that characterize nasalized vowels. It is motivated by the fact that the detection of nasalized vowels is useful in speech recognition, since regions can be identified in the speech signal where a nasal consonant may be present, and where the vocal tract resonances are distorted. Our study consists of several steps. First, an acoustic study was performed using utterances from a large database in order to propose potential measures of nasality. Next, automatic algorithms were developed to extract these measures, and their utilities were established through examination of a large amount of data. Finally, recognition experiments were performed using these measures. The system detected nasalized vowels with an accuracy of approximately 74%, when tested on one speaker at a time, and trained on the speech of the remaining speakers in the database.