Speech encoding process combining written and spoken message codes

Claim 1

A process for encoding digital speech information to represent human speech as audible synthesized speech with a reduced speech data rate while retaining speech quality in the reproduction of the encoded digital speech information as audible synthesized speech, said process comprising: encoding a sequence of input data in the form of a plurality of phonological linguistic units representative of a written version of a message to be coded to provide a first encoded speech sequence corresponding to the written version of the message to be coded; encoding a second sequence of input data derived from a spoken version of the same message to which the written version pertains in the form of a plurality of phonological linguistic units and intonation parameters corresponding thereto, wherein the phonological linguistic units are equivalent to the phonological linguistic units of said first encoded speech sequence, thereby providing a second encoded speech sequence including intonation parameters of the speech as a portion thereof and corresponding to the spoken version of the message to be coded; combining with the first encoded speech sequence corresponding to the written version of the message to be coded, the portion of the second encoded speech sequence corresponding to the spoken version of the message to be coded which includes the intonation parameters of the speech; and producing a composite encoded speech sequence corresponding to the message from the combination of the first encoded speech sequence and the encoded intonation parameters of the speech included in the portion of the second encoded speech sequence.