Abstract: An apparatus and method for adjusting the friendliness of a synthesized speech and thus generating synthesized speech of various styles in a speech synthesis system are provided. The method includes the steps of defining at least two friendliness levels; storing recorded speech data of sentences, the sentences being made up according to each of the friendliness levels; extracting at least one of prosodic characteristics for each of the friendliness levels from the recorded speech data, said prosodic characteristics including at least one of a sentence-final intonation type, boundary intonation types of intonation phrases in the sentence, and an average value of F0 of the sentence, with respect to the recorded speech data; and generating a prosodic model for each of the friendliness levels by statistically modeling the at least one of the prosodic characteristics.

Abstract: A spoken dialog system comprises a speech recognition unit for recognizing a user's input speech to generate a character sequence corresponding thereto; a sentence contents database for storing therein a plurality of sentence contents; a knowledge search unit for searching through the sentence contents to find a match for the character sequence, in the sentence contents database; a dialog model unit for delivering the character sequence to the knowledge search unit to receive the sentence contents therefrom, and setting a dialog model by using the sentence contents; a system response unit for generating an output sentence which harmonizes with the user's input speech or expresses a situation of the system; and a speech synthesis unit for converting the output sentence into the output speech.