2. The method of claim 1 wherein forming the statistically derived mapping comprises: accepting a plurality of utterances; measuring statistics from a portion of each of the plurality of utterances; and forming the statistically derived mapping based on a relationship between inputs that each comprise measured statistics from a portion of a single one of the plurality of utterances and outputs that each comprise feature normalization parameters calculated from multiple ones of the plurality of utterances.
2. The method of claim 1 wherein forming the statistically derived mapping comprises: accepting a plurality of utterances; measuring statistics from a portion of each of the plurality of utterances; and forming the statistically derived mapping based on a relationship between inputs that each comprise measured statistics from a portion of a single one of the plurality of utterances and outputs that each comprise feature normalization parameters calculated from multiple ones of the plurality of utterances. 5. The method of claim 2 wherein the feature normalization parameters corresponding to the plurality of utterances comprise means and variances over time of the plurality of utterances.