1. A method for editing speech, comprising: inputting a plurality of texts to generate representative speech unit waveforms to be used by a phrase concatenation based speech synthesis method; generating speech information from the texts, the speech information comprising phonologic information and prosody information; generating speech waveforms from the speech information by text-to-speech synthesis; dividing the speech waveforms into a plurality of speech unit waveforms based on the phonologic information; searching at least two speech unit waveforms from the plurality of speech unit waveforms, wherein the at least two speech unit waveforms are identical or similar; selecting a representative speech unit waveform from the at least two speech unit waveforms; and storing the representative speech unit waveform into a memory.