18. A speech encoding/decoding system comprising: a recognition section configured to recognize character information from an input speech signal; a detection section configured to detect first prosody information from said input speech signal; an encoding section configured to encode said character information and said first prosody information to code data; a transfer/storage section configured to transfer or store said code data acquired by said encoding section; a decoding section configured to decode said transferred or stored code data to said character information and said first prosody information; a plurality of synthesis unit codebooks storing second prosody information prepared from speech data of different speakers; a controller configured to select one of said synthesis unit codebooks in accordance with one of said first prosody information and a specified type of a synthesized speech by computing error between the first prosody information and the second prosody information and selecting from said synthesis unit codebooks a synthesis unit codebook which minimizes the error; and a synthesis section configured to synthesize a speech signal using said character information and the selected one of said synthesis unit codebooks.
19. The speech encoding/decoding system according to claim 18, wherein said recognition section includes an analysis frame generation section configured to divide said input speech signal into analysis frames, a feature extraction section configured to acquire a feature vector for each of the analysis frames, and a phonetic segment determination section configured to compute a similarity between said feature vector for each of the analysis frames and a feature template vector previously prepared for each phonetic segment to determine a phonetic segment of each of the analysis frames which is used to recognize the character information.