Effects of explicit instruction on noun phrase production in L2 undergraduate writing

While previous research on syntactic complexity development in academic writing recommends incorporating instruction on complex noun phrases into L2 writing curricula, little is known about the effects of such teaching. Therefore, this study examined writing by undergraduate students enrolled in L2 writing courses to determine whether explicit teaching of complex noun phrases could lead to more register-appropriate use of these features. Specifically, this research compared diagnostic and final in-class writing produced by 30 students who received explicit noun phrase instruction and also conducted a separate analysis of 30 papers by writers who did not experience such teaching. Since prompts were found to be a mediating factor in previous research, this variable was also considered in the analysis. The results demonstrate that while both groups displayed patterns of development, targeted instruction led to more frequent use of complex noun phrases in general and of noun phrase modifiers associated with advanced stages of syntactic complexity development. Additionally, while prompts had an effect on some noun phrase features, overall trends in development remained unchanged. These findings support claims from previous research that explicit teaching of complex noun phrases may benefit writers' syntactic complexity development.