The relationship between syntactic complexity and the quality of Chinese as a second language writing for cover letters

Abstract This study investigated the relationship between measures of syntactic complexity at different structural levels and the quality of Chinese as a second language (CSL) writing for practical purposes, focusing on CSL learners with a Japanese background and their writing of cover letters. Results showed that measures based on the topic-comment unit (TC-unit) at the sentence level did not correlate with writing scores of cover letters significantly. At the phrase level, neither the total number of complex noun phrases (NPs) nor the length of complex premodifiers of all NPs had a remarkable correlation with writing scores. However, the complex NP ratio was considerably related to the writing quality, and it explained a large proportion of variance in holistic scores, reaching a medium effect size. These findings demonstrated that phrasal complexity was more effective in predicting the quality of CSL cover letters compared to sentence-level complexity and confirmed that NP complexity measures are more universal when assessing Chinese syntactic complexity across genres. Furthermore, the results differed from previous findings with respect to the effectiveness of number and length indices, calling for greater attention to the ratio index in second language (L2) assessment.