12. The speech synthesis device according to claim 1 , wherein the mouth opening degree generation unit is configured to generate the mouth opening degree, using information generated from the text and indicating the type of the phoneme and a position of the phoneme within an accent phrase.
14. The speech synthesis device according to claim 12 , wherein the mouth opening generation unit is further configured to generate the mouth opening degree using information generated from the text and indicating a part of speech of a morpheme to which the phoneme belongs.