2. The apparatus according to claim 1 , wherein the extracting of the feature words comprises extracting words subjected to intention representation by using more than one type of intention representation and selecting words from the extracted words based on a predefined criteria, as the feature words.
2. The apparatus according to claim 1 , wherein the extracting of the feature words comprises extracting words subjected to intention representation by using more than one type of intention representation and selecting words from the extracted words based on a predefined criteria, as the feature words. 7. The apparatus according to claim 2 , wherein the storage device further stores a dictionary for view point subject to intention representation, and the selecting of words comprises selecting words that are included in the dictionary for viewpoint among words subjected to intention representation, as the feature word.