Pre-recognition measures of speaking rate

Abstract

The accuracy of speech recognition systems is known to be affected by fast speech. If fast speech can be detected by means of a measure of speaking rate, the acoustic as well as language models of a speech recognition system can be adapted to compensate for fast speech effects. We have studied several measures of speaking rate which have the advantage that they can be computed prior to speech recognition. The proposed measures have been compared with conventional measures, viz., word and phone rate on the TIMIT database. Some of the proposed measures have significant correlations with phone rate and vowel duration. We have shown that the mismatch between actual and expected durations of test vowels reduces if the vowel duration models are adapted to speaking rate, as estimated by the proposed measures. These measures can be computed from features commonly employed in speech recognition, do not entail significant additional computational load and do not need labeling or segmentation of unknown utterance in terms of linguistic units.