The current research investigated the correlation between L2 writing proficiency and metadiscourse use in argumentative texts. Metadiscourse is recognized as one of the key strategies for building interaction between a writer and an audience in written discourse. In order to explore the effect of proficiency on the use of metadiscourse markers, the study analyzed two corpora of argumentative essays written by three different proficiency groups of Korean EFL learners and native speakers of English. The focus of analysis was the frequency and range of two main subcategories of metadiscourse, i.e., interactive and interactional resources. The findings revealed marked variations in both quantitative and qualitative aspects of metadiscourse use across different proficiency levels. As proficiency develops, writers showed less reliance on the interactive resources, more balanced use of interactional resources (i.e., hedges and boosters), and expansion in the range of metadiscourse markers used. The findings provide some useful insights into teaching and learning of metadiscourse in persuasive writing which serve to increase a dialogic sense of interaction and audience involvement
