7th International Conference on Narrative & Language Studies, Trabzon, Turkey, 14 - 15 May 2018, pp.47
It is evident that “clauses” are among the underlying structures of English language and it seems that EFL learners mostly have difficulty in using them when they are writing essays. The main purpose of this study is to find out the possible structural problems in the argumentative essays of Turkish EFL learners in terms of the use of relative and noun clauses. Numerous studies have focused on the importance of this problem and the study; therefore, attempts to state the error types in the essays that were analyzed during the study and to seek the possible reasons for these clausal problems. In order to achieve this, the development and use of relative and noun clauses by learners of English in a tertiary level EFL setting were investigated on the basis of a learner corpora compiled by the researcher from the academic writing samples of the students. KTUCLE and LOCNESS learner corpora were used as data collection instruments. The study was carried out during the fall and spring semesters of the 2017- 2018 academic years. At the end of the study, what the learners have overlooked while using these clauses and the sources of the errors they made were evaluated and significant overuse and underuse clausal patterns, as well as error types, were detected and the results were presented in tables and graphics. Some of the error types made by the learners in the study can be categorized as using ungrammatical clausal patterns, transferring the rules of their mother tongue and passivizing the clausal patterns in unexpected ways. Keywords: Corpus, error correction, relative clause, noun clause, Turkish EFL learners.