Abstract

This study examines how disciplinary conventions and first language (L1) backgrounds influence syntactic complexity in academic writing. Drawing on the British Academic Written English (BAWE) corpus, it compares English L1 and Chinese L1 writers across STEM and non-STEM disciplines. The study operationalizes syntactic complexity using 14 syntactic measures across five dimensions: Length of Production Unit, Sentence Complexity, Subordination, Coordination, and Particular Structures. The results indicate that non-STEM writing exhibits higher syntactic complexity than STEM writing, particularly in subordination and nominal structures, reflecting the abstract and argumentative demands of non-STEM disciplines. Meanwhile, English L1 writers show greater syntactic complexity overall, especially in subordination, whereas Chinese L1 writers favor nominalization, reflecting adaptation to academic norms. Notably, disciplinary context appears to shape the influence of L1, with the syntactic difference between English and Chinese L1 writers narrowing in STEM fields due to shared preferences for clarity and concision. These findings highlight the importance of discipline-specific and culturally informed writing instruction, suggesting that academic writing pedagogy in multilingual contexts should incorporate discipline-specific rhetorical training and provide targeted guidance on balancing nominalization with subordination.