A method and apparatus for synthesizing speech. According to one variation of the method and apparatus, a plurality of speech segment data units is prepared for all desired speech waveforms. Speech is then synthesized by reading out from memory the appropriate speech segment data units, and a desired pitch is obtained by overlapping the appropriate speech segment data units according to a pitch period interval. According to a second variation of the method and apparatus, speech segment data units are prepared for only initial speech waveforms and first pitch waveforms, and differential waveforms. With this variation, subsequent pitch waveforms for speech synthesis are generated by combining the first pitch waveform with the corresponding differential waveform. According to a third variation of the method and apparatus, a natural speech segment channel produces natural speech segment data units in the same manner as the first variation, and a synthesized speech segment channel produces speech segment data units according to a parameter method, such as a formant method. The natural speech segments and synthesized speech segments are then mixed to produce synthesized speech.