13. The dialogue system according to claim 11 , wherein the instructions further control the at least one hardware processor to: restrict a size of the extended domain, and apply a weight to the extended input set and makes a request for stoppage of the generation of the extended input set if the weight applied to the extended input set is greater than a predefined value.
13. The dialogue system according to claim 11 , wherein the instructions further control the at least one hardware processor to: restrict a size of the extended domain, and apply a weight to the extended input set and makes a request for stoppage of the generation of the extended input set if the weight applied to the extended input set is greater than a predefined value. 14. The dialogue system according to claim 13 , wherein the weight is differently applied depending on which word of the parsed input set is changed, or depending on a number of words of the parsed input set are changed.