8. The apparatus according to claim 1 , wherein the plurality of speech parameter sequences generated by the parameter generator are at least any of feature amounts which indicate a spectral envelope, feature amounts which indicate periodicity/non-periodicity of speech, and feature amounts which indicate phase characteristics of speech.
8. The apparatus according to claim 1 , wherein the plurality of speech parameter sequences generated by the parameter generator are at least any of feature amounts which indicate a spectral envelope, feature amounts which indicate periodicity/non-periodicity of speech, and feature amounts which indicate phase characteristics of speech. 9. The apparatus according to claim 8 , further wherein the computer is further programmed to reconstruct, by a spectrum reconstructor, a spectral envelope by linearly combining the feature amounts of the spectral envelope and the plurality of basis vectors included in the basis model stored in the basis model storage.