Abstract: A dialogue system include learning initiation unit which receives conversation education domain and target completion condition inconversation education domain and receives user's utterance, voice recognition unit which converts user's utterance into utterance text based on utterance information, language understanding unit which determines user's dialogue act based on converted utterance text and generates logical expression using slot expression corresponding to determined dialogue act and slot expression defined in conversation education domain, dialogue/progress management unit which determines utterance vertex with logical expression similar to that of utterance patterns of plurality of utterance vertices connected to system's final utterance vertex in dynamic dialogue graph and determines utterance vertices connected to determined utterance vertex as next utterance, system dialogue generation unit which retrieves utterance patterns connected to utterance vertex corresponding to determined next utterance