Phrasal complexity in English argumentative writing: Variations across Chinese STEM versus English majors' production and EFL textbook essays

Phrasal complexity is one of the sub-constructs of syntactic complexity, which focuses on phrasal elaboration. This paper identifies the use of different types of phrasal elaboration demonstrated in Chinese college students’ argumentative writing, and investigates phrasal complexity in written production of Chinese EFL tertiary learners majoring in Science, Technology, Engineering and Mathematics (STEM) and English (EM), in comparison to sample essays written by expert writers collected from EFL textbooks (TB). A framework of indices of phrasal elaboration is first established in this study based on grammatical form and syntactic function of phrases. The study finds that the following grammatical forms appear significantly more in argumentative writing collected from textbooks or produced by proficient English majors (with no significant difference found between the two groups): noun phrases functioning as subjects/objects, prepositional phrases (as against to-infinitives, which are significantly fewer) functioning as adverbials, prepositional phrases as noun post-modifiers and their multiple embedding, multiple attributive embedding as pre-modifiers, and appositive phrases. Pedagogical implications for L2 English writing are provided.