4. The method of claim 1 , wherein authenticating the input speech signal based on the at least one speaker-specific distribution value further comprises: decomposing at least one phoneme-independent spectral feature vector of the input speech signal into at least one speaker-specific characteristic unit; comparing the at least one speaker-specific characteristic unit to the at least one speaker-specific distribution value; and authenticating the input speech signal if the at least one speaker-specific characteristic unit is within a threshold limit of the at least one speaker-specific distribution value.
4. The method of claim 1 , wherein authenticating the input speech signal based on the at least one speaker-specific distribution value further comprises: decomposing at least one phoneme-independent spectral feature vector of the input speech signal into at least one speaker-specific characteristic unit; comparing the at least one speaker-specific characteristic unit to the at least one speaker-specific distribution value; and authenticating the input speech signal if the at least one speaker-specific characteristic unit is within a threshold limit of the at least one speaker-specific distribution value. 5. The method of claim 4 wherein decomposing the at least one phoneme-independent spectral feature vector of an input speech signal into at least one speaker-specific characteristic unit further comprises: applying a singular value decomposition to the at least one phoneme-independent spectral feature vector of the input speech signal.