Conditioned variability in voicing offsets

The authors amplify observations by A.K. Krishnamurthy and D.G. Childers (ibid., vol.ASSP-34, p.730-43, Aug. 1986) regarding speech pressure and electroglottographic waveform characteristics at the cessation of voiced speech. They pointed out the great variability in both the abruptness of voicing offset and in the temporal relations of these waveforms at offset. The present authors report that their data confirm that the situation described by Krishnamurthy and Childers occurs frequently. They also report that there can be a decrease in the sharpness of closure of the vocal folds in the final cycles, so that the laryngeal vibration, while causing substantial deflection in the Lx waveform, generates little acoustic energy. This correlates auditorily with a relatively breathy offset, and with an increase in the duration of the open phase with respect to the closed phase of the glottal cycle