The dynamics of syntactic and lexical complexity measures in academic writing

This study explores the L2 production of university students enrolled in an English as a Medium of Instruction (EMI) course, by means of the analysis of the complexity of their academic writing performance. It focuses on syntactic and lexical complexity and their relationship with L2 writing quality and L2 proficiency. The participants were 182 L2 college-level students at difference levels of proficiency in English. The essays were evaluated by means of both global ratings of writing quality and quantitative measures of syntactic and lexical analysis. Results showed that the length of sentences and noun phrases, as well as subordination are all related to writing quality. In addition, the length of noun phrases along with lexical richness and diversity can differentiate proficiency levels. This study shows a greater use of complex phrasal constructions in the writing of more competent third-level students. Finally, our study that at advanced competence levels syntactic and lexical complexity are not synchronous, as syntactic complexity remains stable while lexical complexity continues increasing.