Dialogue system and computer program therefor

A dialogue system, comprising a processor configured to:

• receive an input utterance and generate, as a response utterance original sentence, a response to the input utterance;
• estimate emotion of said input utterance by calculating, for each of a plurality of emotions prepared in advance, an input utterance emotion score indicating a degree of matching between the emotion represented by said input utterance and the plurality of emotions;
• calculate, for said response utterance original sentence, a response utterance emotion score as an emotion score for each of said plurality of emotions;
• and
• generate and output a response utterance by modifying the response utterance original sentence based on values of said input utterance emotion score and said response utterance emotion score, such that:
• when the response utterance emotion score and the input utterance emotion score indicate a similarity between an emotion of the response utterance and an emotion of the input utterance, the response utterance original sentence is modified to denote the similarity between the emotion of the response utterance and the emotion of the input utterance;
• and
• when the response utterance emotion score and the input utterance emotion score indicate a dissimilarity between the emotion of the response utterance and the emotion of the input utterance, the response utterance original sentence is modified to denote the dissimilarity between the emotion of the response utterance and the emotion of the input utterance.