Linguistic Complexity in Cambridge IELTS Academic Reading Passages

Abstract

This study profiles the linguistic complexity of Cambridge IELTS Academic Reading practice passages from volumes 11 to 20 using a multidimensional corpus-based design. It responds to the limited integration of academic vocabulary, phraseology, lexical diversity, syntactic complexity, and cohesion in previous analyses of IELTS preparation materials. The cleaned corpus of 120 reading passages was examined through AWL profiling, KWIC analysis, TAALED, TAALES, TAASSC, and TAACO. Findings show that academic vocabulary is concentrated around research-reporting and explanatory items, especially found, research, environment, and process. KWIC evidence further shows that these items operate as phraseological anchors in patterns such as research shows that, research suggests that, found that the, and found no significant. Automated indices indicate high lexical diversity, strong academic and formulaic lexical load, dense complex-nominal structures, and selective cohesion with limited direct content-word repetition. These patterns suggest that processing difficulty in IELTS Academic Reading practice texts is not produced by vocabulary frequency alone, but by the interaction of academic lexis, phraseological framing, phrasal compression, and implicit cohesion. As a text-internal corpus study, the findings do not measure learner comprehension directly. Pedagogically, they support corpus-informed instruction focusing on academic phrase recognition, noun-phrase unpacking, and paraphrase-based cohesion tracking for high-stakes test preparation. These implications position corpus-informed reading instruction as a creative, evidence-based approach to improving IELTS Academic Reading pedagogy.