11. The apparatus according to claim 1 , further comprising: a plural-speech-units selector configured to select a plurality of speech units for each synthesis unit from the speech-unit storage; a voice converter configured to convert the selected plurality of speech units using the voice conversion function to obtain a plurality of conversion-target-speaker speech units; a fusion unit configured to fuse the selected plurality of conversion-target-speaker speech units to form fused speech units; and a speech-waveform generator configured to concatenate the fused speech units to generate a speech waveform.
1. A speech processing apparatus comprising: a speech storage configured to store a plurality of speech units of a conversion-source speaker and source-speaker attribute information corresponding to the speech units; a speech-unit extractor configured to divide the speech of a conversion-target speaker into a predetermined type of a speech unit to form target-speaker speech units; an attribute-information generator configured to generate target-speaker attribute information corresponding to the target-speaker speech units from the speech of the conversion-target speaker or linguistic information of the speech; a speech-unit selector configured to calculate costs on the target-speaker attribute information and the source-speaker attribute information using cost functions, and selects one or a plurality of speech units with the same phoneme from the speech storage according to the costs to form a source-speaker speech unit; and a voice-conversion-rule generator configured to generate speech conversion functions for converting the one or the plurality of source-speaker speech units to the target-speaker speech units based on the target-speaker speech units and the one or the plurality of source-speakerspeech units.