Whispered speech lacks the vocal chord vibration which is typically used to distinguish voiced and unvoiced consonants, making their discrimination a challenging task. In this work, we objectively and subjectively quantify the amount of discrimination between a voiced (V) consonant and its unvoiced (UV) counterpart using seven V-UV consonant pairs in six Indian languages, in neutral and whispered speech. We also quantify the extent to which the voicing characteristics in a consonant changes from neutral to whispered speech. Experiments using vowel-consonant-vowel (VCV) stimuli demonstrate that the V-UV discrimination reduces from neutral to whispered speech in a consonant specific manner with highest reduction for /ɡ/-/k/ pair and least reduction for /z/-/s/ pair. Interestingly, this reduction in objectively measured discrimination does not directly correlate with the reduction in the V-UV classification accuracy obtained from subjective evaluation. Results from listening test show that the maximum and minimum reduction in the V-UV classification accuracy occur for /ʤ/-/ʧ/ and /v/-/f/ pairs when whispered. Whispered Tamil and Telugu VCV achieve the highest (85.71%) and lowest (58.93%) subjective V-UV classification accuracy respectively, demonstrating the variability in the production and perception whispered consonants across languages.
Bibliographic reference. Meenakshi, G. Nisha / Ghosh, Prasanta Kumar (2015): "A discriminative analysis within and across voiced and unvoiced consonants in neutral and whispered speech in multiple indian languages", In INTERSPEECH-2015, 781-785.