1. A method for predictive encoding comprising: quantizing a parameter vector of an input frame with a strongly-predictive codebook and a weakly-predictive codebook to obtain a strongly-predictive distortion and a weakly-predictive distortion; adjusting a correlation indicator based on a relative correlation of the input frame to a previous frame, wherein the correlation indicator is indicative of the strength of the correlation of previously encoded frames; encoding the input frame with the weakly-predictive codebook unless the correlation indicator has reached a correlation threshold; and wherein adjusting the correlation indicator further comprises using frame erasure concealment to determine the relative correlation of the input frame to the previous frame and wherein using the frame erasure concealent erasure comprises: computing a parameter vector of the previous frame with the frame erasure concealment; computing an erased frame strongly-predictive parameter vector of the input frame using the parameter vector of the previous frame; and comparing a distortion of the erased frame strongly-predictive parameter vector to the weakly-predictive distortion scaled by a predetermined scale factor to determine the relative correlation.