Development of clausal and phrasal complexity in L2 writing: A case of argumentative essays of Korean college students

This study aims to estimate the developmental trajectory of grammatical complexity for L2 writers by investigating the extent to which clausal and phrasal complexity is associated with L2 writing proficiency. The corpus used in this study contained 234 argumentative essays of first-year Korean college students at three proficiency levels. The five clausal and four phrasal features were extracted from the tagged corpus to count the frequency of each complexity feature. Our findings demonstrated an association between writing proficiency and clausal and phrasal complexity. Especially noteworthy was that the main source of complexity at each proficiency level (i.e., finite adverbial clauses, WH relative clauses, of phrases as nominal postmodifiers) showed a gradual increase in complexity in terms of two parameters: structural type and syntactic function. A qualitative follow-up analysis provided a detailed description of differences among developmental levels, especially with respect to the lexical associations of particular complexity features. Pedagogical implications are for using empirically derived developmental stages in creating detailed rating scale descriptors and providing more customized writing courses accordingly.