1. An emotional-speech synthesizing unit that is configured to: calculate in stages degrees of similarity in the emotion and the rhythm between the adjacent words based on context information on the recognized sentence, apply weight to a phoneme candidate corresponding to the each word based on the degrees of the similarity and the probability vector, select the phoneme candidate that has a minimum target pitch, minimum duration time, a minimum distance value of a target pitch contour, and synthesize an emotional speech that corresponds to the recognized sentence in optimal units.