L2 Theme development in Discursive and Experimental undergraduate student writing

To complement earlier studies of writing development in the BAWE corpus of successful student writing (Nesi & Gardner 2012Nesi, H. & Gardner, S. (2012). Genres across the disciplines: Student writing in Higher Education. Cambridge: Cambridge University Press. ; Staples et al. 2016Staples, S., Egbert, J., Biber, D., & Gray, B. (2016). Academic writing development at the university level: Phrasal and clausal complexity across level of study, discipline, and genre. Written Communication, 33(2):149–183. ), we examine the Systemic Functional Linguistics notion of Theme as used by L2 writers across first- and third-year and in two distinctive discourse types: persuasive/argumentative Discursive writing of assignments in the soft disciplines and Experimental report writing of assignments in the hard sciences. Theme analysis reveals more substantial differences across the two discourse types than between first- and third-year L2 undergraduate writing. Textual Themes are consistently more frequent than interpersonal Themes, and some variance is found within subcategories of each. Significant differences in lexical density occur across third-year discourse types and between first- and third-year Experimental writing where a predominance of N+N topical Themes is also found. These findings are important as previous research has tended to focus on L1 Discursive writing.