30. The apparatus of claim 28 , wherein the dialog analyzer comprises: an analyzer that analyzes the user speech into speech elements; a keyword extractor that extracts sentence pattern information, modal information, and discourse marker information using the speech elements; a sentence pattern database that stores information on speech acts and dialog turns resulting from the sentence pattern information, the modal information, and the discourse marker information; and a sentence pattern searcher that searches the sentence pattern database using the sentence pattern information, the modal information, and the discourse marker information to generate the first dialog turn information.
31. The apparatus of claim 30 , wherein the speech element analyzed by the analyzer includes morphemes.