An empirical study on the generation of anaphora in Chinese

The goal of this work is to study how to generate various kinds of anaphora in Chinese, including zero, pronominal, and nominal anaphora, from the syntactic and semantic representation of multisentential text. In this research we confine ourselves to descriptive texts. We examine the occurrence of anaphora in human-generated text and those generated by a hypothetical computer equipped with anaphor generation rules, assuming that the computer can generate the same texts as the human except that anaphora are generated by the rules. A sequence of rules using independently motivated linguistic constraints is developed until the results obtained are close to those in the real texts. The best rule obtained for the choice of anaphor type makes use of the following conditions: locality between anaphor and antecedent, syntactic constraints on zero anaphora, discourse segment structures, salience of objects and animacy of objects. We further establish a rule for choosing descriptions if a nominal anaphor is decided on. We have implemented the above rules in a Chinese natural language generation system that is able to generate descriptive texts. We sent some generated texts to a number of native speakers of Chinese and compared human-created results and computer-generated text to investigate the quality of the generated anaphora. The results of the comparison show that the rules are fairly effective in dealing with the generation of anaphora in Chinese.