Abstract

It is the major purpose of this corpus-based study to investigate Thai EFL students’ L2 English relative clause (RC) acquisition. The data derived from two differing levels of English proficiency (i.e., professional users and intermediate learners) demonstrate the order of difficulty, which largely conforms to the prediction of the Noun Phrase Accessibility Hierarchy. The factor determining the difficulty level in acquiring L2 RCs seems to be markedness. In particular, the subject relative, or the least marked RC type, was found to be the easiest one, followed by the direct object and object of preposition relatives, whereas the most difficult type was evidently the genitive relative, which possesses the highest degree of markedness.