1. A non-dialogue-based learning apparatus, comprising: a speech input unit for inputting speeches; a speech recognition unit for recognizing the input speech; and a behavior and dialogue controller for controlling behaviors and dialogues according to speech recognition results, wherein the behavior and dialogue controller has a topic recognition expert to memorise contents of utterances and to retrieve the topic that best matches the speech recognition results, and a mode switching expert to control mode switching, wherein the mode switching expert switches modes in accordance with a user utterance, wherein the topic recognition expert registers a plurality words in the utterance as topics in first mode, performs searches from among the registered topics, and selects the maximum likelihood topic in second mode.