Generating a Set of Rules to Determine Honorific Expression Using Decision Tree Learning

In Japanese language, the speaker must choose suitable honorific expressions depending on many factors. The computer system should imitate this mechanism to make a natural Japanese sentence. We made a system to determine a suitable expression and named it honorific expression determining system (HEDS). It generates a set of rules to determine suitable honorific expression automatically, by decision tree learning. The system HEDS determines one out of the three classes for an input sentence: the respect expression, the modesty expression and the non-honorific expression and determines what expression the verb is. We calculated the accuracy of HEDS using the cross validation method and it was up to 74.88%.