1. A text-to-speech synthesis apparatus comprising: storage means for storing phoneme data of a plurality of speaker voices; selecting means for selecting at least two speaker voices from said plurality of speaker voices; searching means for searching said storage means for phoneme data of the speaker voices selected by said selecting means; and text-to-speech synthesis processing means for linking said phoneme data of said speaker voices retrieved by said searching means to convert input data into a synthetic speech; wherein said text-to-speech synthesis processing means can convert said input data into a synthetic speech including at least two speaker voices.