Abstract
This paper aims to explore factors related to the difficulty which Japanese EFL learners encounter in judging the grammaticality of English relative clauses. A Grammaticality Judgement Test (GJT) was administrated to 70 Japanese university students whose major was not English. The non-parametric test was employed to analyze the data. Some previous studies have suggested that acquisition or understanding of subject relative clauses (SR) is easier than that of object relative clauses (OR). The data from the GJT differed from that which was found in previous studies with regard to difficulty in judging the grammaticality of relative clauses. A statistically significant difference was found in the number of correct answers between SR and OR in the ungrammatical sentences. This result suggested that the grammaticality judgement of SR is more difficult than that of OR when an ungrammatical SR with no relative pronoun is given. It is argued that the participants could not find clues for recognizing the relative clause structure of the sentences and this makes grammaticality judgement more difficult. These findings imply that the presence of the relative pronoun plays a role as a trigger activating grammar knowledge regarding English relative clauses.
