Meta-discourse markers are an inevitable part of oral proficiency which improve both the quality and comprehension of learners’ speech. While studies of oral meta-discourse have been conducted since the 1980s in a European or US context, they have remained relatively untouched in Iran. Therefore, this study aimed to seek the impact of both explicit and implicit teaching of formal meta-discourse markers on EFL learners’ oral proficiency. To this end, the quantitative data were collected from ninety upper-intermediate students at Shiraz University Language Center. Two groups went through an instruction for an eight-session treatment. However the experimental group ‘B’ (N=45) were instructed the formal meta-discourse markers implicitly, the target formal meta-discourse markers were taught to the experimental group ‘A’ (N=45) explicitly. To compare the participants’ performances, an SOPI (Simulated Oral Proficiency Interview) posttest was administered. The results revealed that the instruction of meta-discourse markers had a positive effect on the learners’ oral outcome. Moreover, the findings showed that learners who received explicit method of teaching formal meta-discourse markers could perform better in speaking than learners who received implicit instruction. The findings can have pedagogical implications for EFL educators and materials developers to enhance learners’ oral proficiency. The findings also provide important insight into the effect of teaching discourse markers and raising learners’ awareness through explicit instruction to make pupils produce more cohesive and coherent speech. Manuscript profile

Discourse markers improve both the quality and comprehension of a written text. This study aimed at investigating the effect of explicit and implicit instruction of formal meta-discourse markers on writ- ing skills. The quantitative data were collected from 90 upper-intermediate students at Shiraz Univer- sity Language Center. Two experimental groups went through an instruction, while the control group did not receive any instruction on formal meta-discourse markers. A pretest-posttest method of as- sessment was employed. After an eight-session treatment, a posttest was administered to compare the participants‟ performances. The results revealed that the instruction of formal meta-discourse markers had a positive effect on the learners‟ writing skills. Moreover, the results showed that learners who received explicit instruction of meta-discourse markers could perform better in writing than learners who received implicit instruction. The findings can have pedagogical implications for EFL educators and materials developers to enhance learners‟ writing skill. Furthermore, the findings provide impor- tant insight into the impact of teaching discourse markers and raising learners‟ awareness through ex- plicit instruction in order to make pupils produce more cohesive and coherent written texts. Besides, it sheds light on the effect of different types of instruction on learning metadiscourse markers and its application in writing skills. Manuscript profile