Corpus-based Development of Syntactic Complexity in EFL Writing

Syntactic complexity has long been taken as a significant factor in determining writing quality by EFL learners. And researchers in recent years have made a lot of efforts to devise and verify a wide range of factors or indicators for the purpose of measuring syntactic complexity or predicting EFL writing quality. The present study discussed bases itself on a self-built learner corpus with data collected over three years, with the aim of determining the applicable indices for predicting beginner writing quality. Based on previous research, the present study takes into account such factors as unit length, verb-VAC complexity, and clausal complexity. The results of pairwise comparisons by year indicate that there are significant differences for some indices but not for others. In terms of unit length, the three indicators of mean length of sentence, mean length of Tuni, and mean length of clause can serve as the main descriptive variables for the development of the language of beginners; for clausal complexity, seven indices: coordinate phrases per T-unit, verb phrases per T-unit, clauses per T-unit, coordinate phrases per clause, complex nominals per Tunit, complex nominals per clause and T-units per sentence, are the reliable indicators for beginner writing development. But indices for noun phrase complexity and verb-VAC complexity show no significant difference in the Kruskal-Wallis tests. The findings provide proof for the conclusion that knowledge and skills of modification, coordination, and subordination form the real difficulties for EFL beginners. It provides implications for coursebook design and classroom teaching where beginners are supposed to focus more on breeding awareness and skills in these aspects