Articulatory speech synthesis using diphone units

Two different parametric models of the vocal tract have been developed. These have been used to obtain area functions for use in an articulatory synthesiser based on the Kelly-Lochbaum (1962) model. Random sampling of the geometric space spanned by the model has been performed to obtain a codebook for use in spectral copy synthesis. A dynamic programming search of this codebook produces intelligible synthetic speech, but the overall quality is limited by the density of codebook entries in articulatory space. To increase the coverage without significantly increasing the codebook size, a method of generating several small codebooks, each of which covers a small amount of acoustic space has been developed. By using codebooks which map the regions of acoustic space defined by voiced diphones, it has been possible to significantly improve the quality of the synthetic speech