Abstract: A method for characterization of a human speech comprises performing (220) of a discrete transform on a speech sample of the human speech. A speech logarithmic power spectrum is created (222) by taking a logarithmic of the speech frequency spectrum. An inverse discrete transform is performed (224) on the speech logarithmic power spectrum into the quefrency domain. Lifterings (226, 228) of the speech cepstrum is performed, giving a high and low end speech cepstrum, respectively. The discrete transform is performed (230) on the high end speech cepstrum, creating a source excitation log-power spectrum. The discrete transform is performed (232) on the low end speech cepstrum, creating a vocal tract filter log-power spectrum. A cepstral separation difference is calculated (234) as a difference between the source excitation log-power spectrum and the vocal tract filter log-power spectrum. The human speech is characterized (238) based on the cepstral separation difference.