VietTESOL International Convention 2026

Although lexical bundles (LBs) have been widely studied, learner variation in LB use remains underexplored. In this study, we employed Latent Profile Analysis (LPA) to identify distinct patterns of LB use among Vietnamese EFL learners in English academic summary writing. A corpus consisting of 220 summaries was compiled and analyzed with AntConc. Four-word LBs were retrieved based on frequency and range thresholds. The extracted LBs were then manually selected and categorized into three discourse functions, achieving acceptable inter-rater reliability (Cohen’s kappa = 0.794). LPA was conducted in R using Gaussian mixture modeling, on 4 indicators: normalized bundle frequency and the proportions of referential, discourse-organizing, and stance LBs. The analysis revealed 6 learner profiles: (1) Discourse-Oriented Users (n = 14), (2) Stance-Oriented Users (n = 23), (3) Referential-Oriented Users (n = 60), (4) Non-Bundle Users (n = 17), (5) Balanced Bundle Users (n = 43), and (6) High-Frequency and Referential-Oriented Users (n = 63). Findings suggest that Vietnamese EFL learners demonstrate substantial variation in their use of formulaic language when constructing academic discourse. While some learners relied heavily on specific functional LBs, others demonstrated a more balanced or minimal use of LBs overall. In addition, a large proportion of learners employed referential bundles more frequently than other LB types, suggesting a tendency toward descriptive and informational expression in summary writing. The study also provides pedagogical implications for teaching LBs and developing academic writing instruction in EFL contexts.