Vol. 3, Issue 10, Part C (2017)

Abstract
This study aims at investigating the discourse errors in the use of grammatical cohesive devices in argumentative texts written by Yemeni EFL learners. It particularly aims at identifying the different categories and the most frequent category of errors in the use of grammatical cohesive devices in argumentative texts produced by the learners. For the purpose of collecting the data, the study was conducted on twenty four students of the third level in the Department of English at the Faculty of Education-Saber, Aden University, Yemen. The students were required to write an argumentative text on one of two topics given to them. Regarding the data analysis, the study utilized qualitative and quantitative procedures. The qualitative procedures were used for identifying the categories of errors whereas the quantitative ones were utilized to identify the most frequent category made in the learners’ writings. The quantitative analysis made use of the statistical procedures of counting errors within each category and then calculating the percentage of each category of the errors. The results of the study indicated that the learners committed errors of reference, errors of substitution and ellipsis, and errors of conjunctions. The findings also revealed that the category of errors in the use of reference ties was the most problematic category in which the learners made the most frequent errors whereas the category of errors in the use of substitution and ellipsis was the least frequent one. Thus, these errors were distributed among the categories according to the frequency as follows: errors of reference; errors of conjunction; and errors of substitution and ellipsis, respectively.