1. An automatic speech translation system based on a corresponding sentence template, the system comprising: a speech recognizer searching for a sentence template network in response to an input speech signal and outputting the best matching sentence template and corresponding words for the classes included in the sentence template; a language translator receiving the sentence template and the words which are generated by the speech recognizer, and outputting a translated sentence template and translated words using a corresponding sentence template dictionary and a corresponding word dictionary, respectively; and a speech synthesizer searching for prosody data corresponding to the translated sentence template in a sentence template prosody data dictionary and synthesizing speech based on the search result, and outputting the speech.