Abstract
In first language studies, the Toulmin model of argumentation has become a prominent analysis and assessment method for English argumentative essays. However, there hasn't been much study on using argument theory to scaffold teaching in practice in second language classrooms. As a broad group of English learners, Chinese university students face numerous challenges when writing argumentative essays in English. As a result, in order to broaden the writing pathway for second language learners, this study employs the Toulmin argumentation model as a pedagogical scaffold. The effects of the argumentation model as a pedagogical scaffold on students' argumentative essay writing were examined on the pre-test and post-test results from both experimental and control groups. Overall scores and argumentative elements in terms of quantity, type, and quality were examined respectively. The mixed-effects model revealed that introducing the Toulmin model of argumentation into the scaffolding method had a significant impact on most argumentative elements in students' writing. The practical pedagogical implications and effects of Toulmin argumentative model have been discussed in detail in this paper.