1 LEXICAL IDENTITY AND DISCIPLINARY DIFFERENTIATION IN ENGLISH PROGRAM CURRICULA: A CORPUS-BASED KEYNESS ANALYSIS ACROSS 38 THAI RAJABHAT UNIVERSITIES

Abstract

Curriculum design in higher education has traditionally relied on expert judgment rather than systematic linguistic analysis, leaving the lexical coherence and disciplinary identity of course descriptions largely unexamined. This study addresses that gap through a macro level corpus analysis of English course descriptions drawn from 38 Rajabhat universities across Thailand, spanning three professional tracks, namely General English (GE), Business English (BE), and English Education (ED). A corpus of 177,065 words compiled from 4,353 course description files was analyzed using keyness statistics, specifically Log-Likelihood, Log Ratio, and Juilland's D, with the British National Corpus and the Leipzig General Written English corpus serving as reference corpora. The findings show that 95 percent of the top 20 keywords differed significantly across curriculum types (p < .001). The BE curriculum was grounded in commercial discourse, the ED curriculum in pedagogical and institutional language, and the GE curriculum in humanities and translation related vocabulary, reflecting distinct English for Specific Purposes (ESP) orientations across the three tracks. A subsequent MANOVA confirmed a multivariate difference with a large effect size for the word cluster comprising "principles," "educational," and "management" (Pillai's Trace = 0.175, p < .001). Taken together, these results characterize the lexical differentiation underlying English curriculum discourse and offer a corpus-based framework for curriculum evaluation that can be applied in comparable English as a Foreign Language (EFL) context.