Abstract
When we are translating Japanese nouns into English, we face the problem of articles and numbers which the Japanese language does not have, but which are necessary for the English composition. To solve this difficult problem we classified the referential property and the number of noun phrases into three types respectively: generic, definite and indefinite for the referential property of noun phrases, singular, plural, and uncountable for the number of noun phrases. This paper shows that the referential property and the number of noun phrases can be estimated fairly reliably by the words in the sentence. Many rules for the estimation were written in forms similar to rewriting rules in expert systems with scores. Since this method uses scores, it is good to deal with vague problems like referential properties and numbers. We obtained the correct recognition scores of 85.5% and 89.0% in the estimation of referential property and number respectively for the sentences which were used for the construction of our rules. We tested these rules for some other texts, and obtained the scores of 68.9% and 85.6% respectively. These referential properties and numbers of noun phrases will be used not only for determination of articles and numbers but also for anaphora resolution and discourse analysis.