The present invention provides a method and apparatus for text to speech conversion, and a method and apparatus for adjusting a corpus. The method for text to speech comprises: text analysis step for parsing the text to obtain descriptive prosody annotations of the text based on a TTS model generated from a first corpus; prosody parameter prediction step for predicting the prosody parameter of the text according to the result of text analysis step; speech synthesis step for synthesizing speech of said text based on said the prosody parameter of the text; wherein descriptive prosody annotations of the text include prosody structure for the text, the prosody structure of the text is adjusted according to a target speech speed for the synthesized speech. The present invention adjusts the prosody structure of the text according to the target speech speed. The synthesized speech will have improved quality.