1. A system for generating synthetic speech, comprising: a phoneme segment storage section operable to store a plurality of phoneme segment data pieces indicating a plurality of sounds of phonemes which are different from each other; and a synthesis section operable to generate voice data representing synthetic speech of text by receiving an inputted text, reading out phoneme segment data pieces that correspond to respective phonemes indicating the pronunciation of the inputted text, and connecting the read-out phoneme segment data pieces to each other; a computing section operable to compute a score indicating naturalness of the synthetic speech of the text, on the basis of the voice data; a paraphrase storage section operable to store a plurality of notations each comprising a word or phrase, the plurality of notations comprising a plurality of first notations and a plurality of second notations, each second notation being a paraphrase of a respective first notation; a replacement section operable to search the text for a notation matching any of the first notations and to replace a matching notation with the second notation corresponding to the first notation; and a judgment section operable to receive the score computed by the computing section and determine whether the score indicates the synthetic speech is sufficiently natural, and: if the score indicates the synthetic speech is sufficiently natural, output the generated voice data; and if the score indicates the synthetic speech is not sufficiently natural, cause the replacement section to generate revised text by replacing at least one other notation in the inputted text matching a first notation with a corresponding second notation, and cause the synthesis section to generate voice data for the revised text.
1. A system for generating synthetic speech, comprising: a phoneme segment storage section operable to store a plurality of phoneme segment data pieces indicating a plurality of sounds of phonemes which are different from each other; and a synthesis section operable to generate voice data representing synthetic speech of text by receiving an inputted text, reading out phoneme segment data pieces that correspond to respective phonemes indicating the pronunciation of the inputted text, and connecting the read-out phoneme segment data pieces to each other; a computing section operable to compute a score indicating naturalness of the synthetic speech of the text, on the basis of the voice data; a paraphrase storage section operable to store a plurality of notations each comprising a word or phrase, the plurality of notations comprising a plurality of first notations and a plurality of second notations, each second notation being a paraphrase of a respective first notation; a replacement section operable to search the text for a notation matching any of the first notations and to replace a matching notation with the second notation corresponding to the first notation; and a judgment section operable to receive the score computed by the computing section and determine whether the score indicates the synthetic speech is sufficiently natural, and: if the score indicates the synthetic speech is sufficiently natural, output the generated voice data; and if the score indicates the synthetic speech is not sufficiently natural, cause the replacement section to generate revised text by replacing at least one other notation in the inputted text matching a first notation with a corresponding second notation, and cause the synthesis section to generate voice data for the revised text. 5. The system according to claim 1 , wherein the synthesis section includes: a word storage section for storing a reading way of a plurality of words in association with a notation of the plurality of words; a word search section for searching the word storage section for a word whose notation matches with the notation of each of the words contained in the inputted text, and for generating a reading way of the text by reading the reading ways corresponding to the respective searched-out words from the word storage section, and then by connecting the reading ways to each other; a phoneme segment search section for generating the voice data by retrieving a phoneme segment data piece representing a tone closest to tone of each phoneme determined based on the generated reading way, from the phoneme segment storage section, and then by connecting the plurality of retrieved phoneme segment data pieces to each other, and wherein the computing section is operable to compute, as the score, a difference between the tone of each phoneme determined based on the generated reading way, and the tone indicated by the phoneme segment data piece retrieved in correspondence to each phoneme.