Studies have found that morphology awareness could assist writers to increase productive vocabulary (e.g. Green et al., 2003;McCutchen & Stull, 2015), reduce vocabulary errors (e.g. Karakas, 2012;Ririn, 2010), and produce complex sentence structures using various forms of words. Postgraduate students as second language users of English (L2) were found to experience lack of vocabulary and have difficulties in their academic writing. Researchers have been concentrating on examining the relationship of morphological awareness with vocabulary reading, reading comprehension, receptive vocabulary knowledge, and spelling; however, there is still a shortage of studies examining the relationship of morphological awareness with academic writing, particularly among L2 postgraduate students. Therefore, this study aims to examine the correlation of morphological awareness with academic writing and investigate the extent to which the dimensions of morphological awareness and productive vocabulary knowledge predict the success of postgraduate students' academic writing in an ESL context. The results showed that there was a significant correlation between morphological awareness and academic writing. The synthetic dimension of morphological awareness had a stronger contribution than the analytic dimension to the L2 postgraduate students' academic writing. The results also showed that learning and teaching morphology could bring benefits to L2 postgraduate students, allowing students to improve their productive writing skills and enabling them to produce texts and convey their ideas meaningfully.

The current paper represents a conceptual framework for the relationship between morphological awareness and academic writing directly and indirectly through the mediation of productive vocabulary knowledge. Reviewing the literature guided the researcher in developing the conceptual framework of the current study. The present study suggested a strategy which may help the second language postgraduate students in enhancing their productive vocabulary knowledge regarding the size of words they know and how deep they know about them, which eventually would help the students in improving their academic writing. Moreover, the current paper addresses the relationship between morphological awareness and the different language skills conceptualised in the literature review. It also delineates the role of vocabulary knowledge and academic vocabulary to academic writing. Eventually, a conceptual framework regarding the direct relationship between morphological awareness and academic writing among the second language postgraduate students and the indirect relationship between both of them through the mediation of productive vocabulary knowledge is suggested in this current paper.

The significance of vocabulary knowledge in academic development and having a sufficient vocabulary in language learning cannot be overstated. Research has shown that postgraduate students studying English as a second language (L2) lack vocabulary and require improving it. This research study was conducted to investigate the role of morphological awareness and its relation to productive vocabulary breadth and explore the function of teaching L2 postgraduate students in intervention for improving their productive vocabulary breadth. Thirty L2 postgraduate participants were involved in an intervention. The intervention included 11 sessions of morphological awareness instructions. The students’ morphological awareness was tested using the Morphological Identification Test (MIT) and the Morphological Structure Awareness Test (MSAT), while productive vocabulary breadth was tested using the Productive Vocabulary Level Test (PVLT). A significant relationship was found between morphological awareness and productive vocabulary breadth. The synthetic aspect of morphological awareness was more closely related to the participants’ productive vocabulary breadth than the analytic aspect. The morphological awareness intervention was effective and beneficial in increasing the students’ productive vocabulary breadth. The results may indicate the benefits of teaching and learning morphology to L2 postgraduate students, especially for effective vocabulary building.

An academic writing test was administered in which the participants were asked to write about one of the two academic writing topics provided to them: "In some countries, the average weight of people is increasing and their levels of health and fitness are decreasing. What do you think are the causes of these problems and what measures could be taken to solve them?" and "In many countries, the amount of crime is increasing. What do you think are the main causes of crime? How can we deal with those causes?"