Mouth rhythm as a "packaging mechanism" of information in speech: A proof of concept.

This paper postulated and tested the possibility that the mouth rhythm functions as a "packaging mechanism" of information in speech. Cross-spectral analysis between two time series of mouth aperture size [parameterized as sample-by-sample interlip distances, i.e., o(t)] and information variations in speech [parameterized as frame-by-frame spectral entropy values, i.e., h(t)] was employed to reveal their underlying spectro-temporal relationship. Using a corpus containing more than 1000 utterances produced by a typical British English speaker, it was observed that both signals share slow recurring rates corresponding to the stress and syllable, with a slight phase lag of h(t) behind o(t) in the vicinity of 5 Hz.