1. A computer-readable medium having computer-executable instructions for performing steps comprising: using a prior model of static aspects of clean speech to produce a static-based predicted value; using a prior model of dynamic aspects of clean speech to produce a dynamic-based predicted value; applying a noisy feature vector representing a frame of noisy speech to an acoustic environment model to produce an acoustic environment-based predicted value; and combining the static-based predicted value, the dynamic-based predicted value and the acoustic environment-based predicted value to form at least one component of a noise-reduced feature vector.