A speech synthesis apparatus includes a text obtaining device that obtains text data for speech synthesis from the outside, a language processor that carries out morphological analysis/parsing to the text data, a prosodic processor that outputs, to a speech synthesizer, a synthesis unit string based on the prosodic and language related attributes of the text data such as accents and word classes, the speech synthesizer that generates synthesized speech from the synthesis unit string, and a speech waveform output device that reproduces a prescribed amount of output synthesized speech after it is accumulated or sequentially as it is output.