Sentences corresponding to internal statuses of a robot device or the like are created and uttered, thereby expressing the internal statuses. The robot device or the like comprise means for recognizing an external status, and means for generating an emotion based on the internals status, whereby a change in the emotion is reflected upon a dialogue. The internal status is not associated with a sentence, but it exists independently of the system and is always varied depending on various external inputs and internal changes of the system. Accordingly, even when the same question is made on the robot device or the like, the contents of a reply are changed depending on the internal status at that time, and a manner of providing a reply also differs depending on the internal status.