1. A text-independent speaker verification system comprising: an enrollment stage that includes a digital signal processing block, a feature extraction block and a pattern matching block; a threshold generation stage that includes a digital signal processing block, a feature extraction block and a threshold generation block; and a verification stage that includes a digital signal processing block, a feature comparison block and a decision block; wherein the pattern matching block incorporates template modeling with vector quantization; and wherein the verification stage incorporates an adaptive decision verdict; and wherein the speaker-verification system operates in a first mode of operation and thereafter in a second mode of operation, the first mode of operation comprising: the enrollment stage for receiving speech from a known speaker, for processing the received speech, and for generating a codebook and speaker voice print values; and the threshold generation stage for receiving additional speech from the known speaker, for processing the additional speech, for comparing the result to the codebook, and for generating and recording a threshold representing an acceptable deviation from the codebook; and the second mode of operation comprising: the verification stage for receiving speech, which is purported to be from the known speaker, for processing the speech, for comparing the result to the codebook and the threshold, and for determining whether the speaker is the known speaker or an imposter; wherein in the case that the speaker is verified as the known speaker, the verification stage records a deviation between the speech received by the verification stage and the codebook, outputs a deviation message indicating the deviation of the additional speech, and calculates a new threshold from the recorded deviation and from other previously recorded deviations generated from the first and second modes of operation.