Exploring the Impact of WeChat Multimodality Affordances on Chinese EFL Undergraduates' Writing Development

Social media are increasingly integrated into foreign language education, offering new opportunities for multimodal writing practice. However, most existing studies focus on English-language-dominated platforms that are often inaccessible to learners in non-English-speaking contexts like China. This study explores the impact of WeChat's multimodal affordances on Chinese EFL undergraduates' argumentative writing within the framework of the College English Test. A mixed-methods approach was employed, combining a quasi-experimental design involving two classes (N=80) and semi-structured interviews conducted with nine students. Students in the experimental group significantly outperformed the control group in content (M=24.28 vs. 20.05; p< .01), organization (M=17.50 vs. 15.10; p< .01), and vocabulary (M=17.13 vs. 14.33; p< .01). Semi-structure interviews revealed that WeChat multimodal features enhanced clarity, creativity, and motivation but also led to distractions and revealed students limited multimodal literacy. This is the first known study to examine WeChat's multimodal affordances across specific dimensions of EFL writing in a Chinese context. Results demonstrate that WeChat's combination of text, audio, and visual features yields substantial gains in content development, vocabulary use, and organizational clarity, while gains in grammar and mechanics remain modest, highlighting the importance of guiding students to deploy multimodal resources with intentionality. The study offers practical implications for integrating locally relevant social media tools into EFL writing pedagogy and underscores the need for targeted instructional support to cultivate learners' multimodal competence.