1. A data processing device for generating, from a preset code, filter data to be afforded to a speech synthesis filter adapted for synthesizing the speech based on linear prediction coefficients and a preset input signal, comprising: code decoding means for decoding said code produced by encoding original filter data, to output decoded filter data; acquisition means for acquiring preset tap coefficients as found by carrying out learning, wherein said tap coefficients are used to predict the original filter data from said decoded filter data; and prediction means for carrying out preset predictive calculations, using said tap coefficients and the decoded filter data, to find prediction values of said filter data, to send the so found prediction values to said speech synthesis filter for use as linear prediction coefficients in said speech syntheses filter.