Abstract: The present invention includes a morpheme extracting unit 420 configured to extract, based on a character string corresponding to input information, at least one morpheme constituting a minimum unit of the character string, as first morpheme information, a topic search unit 340 configured to compare the first morpheme information extracted at the morpheme extracting unit 420 with topic titles, and to search a topic title corresponding to the first morpheme information from among the topic titles, and a reply retrieval unit 350 configured to retrieve, based on the topic title searched at a topic identification information search unit 320, a reply sentence associated with the topic title.

Abstract: The present invention is a conversation control apparatus for carrying out conversation control based on both speech content and conversation state and information acquired from outside, and carrying out natural responses. This apparatus comprises a conversation database storing a plurality of items of conversation topic specifying information, a conversation control unit for selecting a reply sentence using conversation topic specifying information determined using the conversation history and conversation information, and an environment recognition unit for acquiring environment recognition information, wherein the environment recognition unit generates event information based on acquired environment recognition information, and the conversation control unit selects a reply sentence based on the event information.

Abstract: An automatic conversation apparatus includes a speech recognizing unit receiving a speech signal and outputting characters/character string corresponding to the speech signal as a recognition result; a speech recognition dictionary storing unit storing a language model for determining candidates corresponding to the speech signal; a conversation database storing plural pieces of topic specifying information; a sentence analyzing unit analyzing the characters/character string outputted from the speech recognizing unit; and a conversation control unit storing a conversation history and acquiring an answer sentence based on an analysis result of the sentence analyzing unit.