The effects of machine translation (MT) use on the writing quality and perceptions of L2 writers across proficiency levels: A longitudinal examination

This study investigated the influence of using machine translation (MT) for second language (L2) writing on the subsequent L2 writing produced without the use of MT. A total of 130 Korean university learners of L2 English at three proficiency levels generated English essays without utilizing MT during the first and last classes of a general English course. Between these two occasions of writing, they wrote in English employing MT on four occasions. The first and final essays were compared via syntactic complexity, accuracy, lexical complexity, and fluency (CALF) measures. The learners were also asked about their attitudes toward and use of MT. The results indicated that MT use affected L2 writing differently according to proficiency levels. The advanced learners and the low-intermediate learners, who represented the lowest-level learners in this study, improved more in terms of lexical complexity and syntactic complexity, respectively. The high-intermediate learners benefited less than those in the other two proficiency groups. Regarding accuracy and fluency, the learners across the proficiency levels produced higher quality writing. Concerning their attitudes toward MT, the lower their proficiency levels were, the more positive their attitudes were.