Linguistic variation in two written academic sub-registers

The present study aims to compare abstracts written by graduate students and internationally-published authors using Biber’s (1988) Multi-Dimensional (MD) model. To this end, two corpora of abstracts (1800 texts each) from research articles (RA) published in top international Applied Linguistics journals, and theses completed in the same field were compiled. We compared the two corpora with regard to three of Biber’s (1988) dimensions: involved versus informational production; elaborated vs. situation-dependent reference; and abstract vs. non-abstract style. Our results revealed that RA abstracts and thesis abstracts are similar when compared to non-academic registers of English, but different when compared to each other. Relative to thesis abstracts, RA abstracts are more informational but less elaborated and less impersonal. Interestingly, we found that RA/thesis abstracts differ from Biber’s (1988) academic prose register along the three dimensions. Our findings can further our understanding of the differences between RA and thesis abstracts, thus contributing to the instruction of academic writing at the graduate level.