1. A method for speech recognition, comprising the steps of: determining active Gaussians related to a first feature stream and a second feature stream by labeling at least one of the first and second streams; determining active Gaussians co-occurring in the first stream and the second stream based upon joint probability; reducing a number of Gaussians computed for the second stream based upon Gaussians already computed for the first stream and a number of Gaussians co-occurring in the second stream; and decoding speech based on the Gaussians computed for the first and second streams.