1. A method of noise-robust speech classification, comprising: inputting classification parameters to a speech classifier from external components; generating, in the speech classifier, internal classification parameters from at least one of the input classification parameters; setting a Normalized Auto-correlation Coefficient Function threshold, wherein setting the Normalized Auto-correlation Coefficient Function threshold comprises: increasing a first voicing threshold for classifying a current frame as unvoiced when a signal-to-noise ratio (SNR) fails to exceed a first SNR threshold, wherein the first voicing threshold is not adjusted if the SNR is above the first SNR threshold, and increasing an energy threshold for classifying the current frame as unvoiced when the noise estimate exceeds a noise estimate threshold, wherein the energy threshold is not adjusted if the noise estimate is below the noise estimate threshold; and determining a speech mode classification based on a the first voicing threshold and the energy threshold.