On Extending VTLN to Phoneme-specific Warping in Automatic Speech Recognition

Phoneme- and formant-specific warping has been shown to decrease formant and cepstral mismatch. These findings have not yet been fully implemented in speech recognition. This paper discusses a few reasons how this can be. A small experimental study is also included where phoneme-independent warping is extended towards phoneme-specific warping. The results of this investigation did not show a significant decrease in error rate during recognition. This is also in line with earlier experiments of methods discussed in the paper.

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