1. A language understanding apparatus comprising: a storage section that stores concept structure data indicating a correlation between a tree structure of a concept to be used in a domain and a concept representation specifying the concept, frame definition data corresponding to a concept and indicating a correlation between one or more semantic frames for representing the concept by another concept, and one or more slots to be used in the one or more semantic frames, and slot definition data indicating a concept to be used as a slot; a phrase interpreter that receives input utterance data detects a concept representation included in an utterance content indicated by the input utterance data by referring to the storage section, and reads information of a concept corresponding to the detected concept representation from the storage section; and a bidding section that reads information on a slot of a semantic frame corresponding to the concept indicated by the information read by the phrase interpreter and information on a concept corresponding to the slot by referring to the storage section, specifies, for each semantic frame read, from the concept representation detected by the phrase interpreter, a concept representation corresponding to a concept corresponding to each slot of the semantic frame or a subordinate concept of that concept, and a concept representation whose slot of another semantic frame is not bidden and repeats bidding the slot for the specified concept representation, thereby generating slot allocation table data indicating a bidding result.