Grammatical Error Patterns in Thai EFL University Writing: A Surface Strategy Taxonomy Analysis

Abstract

The purpose of this study is to investigate the grammatical errors in academic writing by Thai EFL university students and to investigate the relationships between these errors and proficiency, institutional context, and extracurricular English exposure. Each of the two institutions examined the English essay writings by sixty second-year Thai students for errors using the Surface Strategy Taxonomy. A total of 138 grammatical errors were discovered in the data. Although addition (14.8%) and misordering (1.5%) errors were less frequent, misformation errors (47.5%) and omission errors (36.2%) constituted over 83% of all errors. Chi-square analyses found no significant differences in error patterns between the two universities (all p > .05, Cramér’s V ≤ 0.23). A two-way ANOVA showed a significant main effect of English proficiency on total error count (p < .001, partial η² ~ .30), but no effect of university and no interaction. Proficiency level was the sole significant predictor of error frequency (β = –0.56, p <.001, 95% CI for B [–3.0, –1.0]), as confirmed by a multiple regression. University affiliation (β = 0.03, p =.70) and self-reported extracurricular English exposure (β = –0.08, p =.40) did not independently predict errors. The statistics demonstrate that students who demonstrated exceptional skill made significantly fewer errors than those who exclusively enrolled in a particular institution. The ongoing grammatical challenges that Thai learners encounter in the acquisition of a second language, particularly with respect to verb forms, tense, and articles, are emphasized by the frequency of omissions and misformations.