Thesis (Ph.D.)--Chulalongkorn University, 2009

This study examined the English relative clause (ERC) in the interlanguage of Thai EFL learners. The participants in the study were recruited from first-year students at Thammasat University, divided into two groups according to their English proficiency in order for the researcher to clearly observe the interlanguage development of ERCs. The major research instruments used to elicit ERCs were a descriptive essay and a descriptive speaking task. The participants were also asked to translate Thai sentences comprising a relative clause into English. This translation task was considered a supplementary tool for an investigation of the participants’ avoidance behavior. The data were quantitatively analyzed through both descriptive and inferential statistics. Qualitative analyses were conducted as well based on a framework which is a combination of the Noun Phrase Accessibility Hierarchy (NPAH) and the Perceptual Difficulty Hypothesis (PDH). The findings of this research demonstrate that Thai EFL learners in both proficiency groups seemed to acquire ERCs in a similar way as other English learners from different L1 backgrounds. Thai learners of English apparently had an order of ERC-type acquisition which followed the prediction of the NPAH in that the subject relative was acquired first and prior to the direct-object relative, which was in turn acquired earlier than the object-of-preposition relative. The genitive relative appeared to be the last type which they acquired. Furthermore, they were found to produce resumptive pronouns although their native language as well as the target language disallows them. In addition to the NPAH, the learners’ development of ERCs also seemingly conformed to the PDH since the acquisition of right-embedded ERCs obviously preceded that of center-embedded ERCs. With respect to relative marker acquisition in both groups of proficiency, that seemed to be acquired first, whereas whose was viewed as the last. The results also reveal that the learners’ problems in learning ERCs are attributed to first-language and previous-training transfer, overgeneralization, and avoidance.