Acoustic Characterization of Word-Final Glottal Stops in Mizo and Assam Sora

The present work proposed an approach to characterize the word-final glottal stops in Mizo and Assam Sora language. Generally, glottal stops have more strong glottal and ventricular constriction at the coda position than at the onset. However, the primary source characteristics of glottal stops are irregular glottal cycles, abrupt glottal closing, and reduced open cycle. These changes will not only affect the vocal quality parameters but may also significantly affect the vocal tract characteristics due to changes in the subglottal coupling behavior. This motivates to analyze the dynamic vocal tract characteristics in terms of source behavior, apart from the excitation source features computed from the Linear Prediction (LP) residual for the acoustic characterization of the word-final glottal stops. The dominant resonance frequency (DRF) of the vocal tract using Hilbert Envelope of Numerator Group Delay (HNGD) are extracted at every sample instants as a cue to study this deviation. The gradual increase in the DRF and significantly lower duration for which subglottal coupling is occurring is observed for the glottal stop region for both the languages.