Frequency Effect of Formulaic Sequences on CAF in Academic Writing: Examples from L2 Master's Theses

This study was conducted to explore the individual uses of formulaic sequence (FS) frequency and their effects on complexity, accuracy, and fluency (CAF) in academic writing. Data was collected from the conclusion sections of a self-compiled corpus of 30 L2 master's theses. Statistical analysis revealed several notable conclusions. 1) Student writers tend to make repetitive use of particular FSs in single texts. 2)FS use has a significant frequency effect on fluency, and the high-frequency group slightly outperforms the low-frequency group. 3) FS use has a certain frequency effect on accuracy, and the high-frequency group demonstrates the strongest correlation between FS frequency and accuracy. 4) FS use has a significant frequency effect on lexical complexity, and the low-frequency group slightly outperforms the high-frequency group. In the low-frequency group, FS use has a significant frequency effect on syntactic complexity as well. Finally, 5) The results support Skehan's trade-off effect, a competition between CAF, which, to a certain degree, is affected by individual uses of FS frequency. The low-frequency group displays a greater trade-off effect than the high-frequency group.