1. A method for concealing the effects of frame errors in frames to be decoded by a decoder in providing synthesized speech, the frames being provided over a communication channel to the decoder, each frame providing parameters used by the decoder in synthesizing speech, the method comprising: a) determining whether a frame is a bad frame; and b) providing a substitution for the spectral parameters of the bad frame based solely on spectral parameters for recently previously received good frames and including an at least partly adaptive mean of the spectral parameters of a predetermined number of the most recently previously received good frames.