Lexical diversity and CEFR vocabulary in critical academic reading passages: A conceptual replication

Background and Purpose: Critical academic reading skills demand learners to engage in higher-order reading skills which require advanced lexical knowledge. The two dimensions of lexical knowledge, namely lexical diversity and vocabulary variety, however, are mostly assessed in isolation using unstable measurement instruments, hence giving misleading results. The purpose of this study was to examine these two dimensions in critical academic reading passages through an integrated approach using a more reliable measurement instrument. Methodology: The corpus consisted of 32 selected reading passages. They were first cleaned to remove any interference, such as numbering that might affect the lexical calculation, before being converted to plain text format. The Text Inspector was then used to generate the Measure of Textual Lexical Diversity (MTLD) and CEFR vocabulary difficulty levels for all passages. The scores were then analysed descriptively to examine the patterns of lexical diversity and CEFR vocabulary distributions across the passages. Additionally, Spearman’s rho correlational analysis was conducted to examine the relationship between MTLD scores and CEFR-based vocabulary levels. Findings: All 32 examined passages generally exhibit high lexical diversity, with many common and basic words. Lexical diversity was found to increase when advanced vocabulary was added to the passage, indicating a significant positive correlation between the two dimensions. Contributions: The integrated approach in lexical analysis adopted in this study results in a comprehensive picture of lexical complexity rather than using the single metric alone, hence offering a clearer and fairer approach for instructors in evaluating and selecting reading passages to be used with students. Keywords: CEFR profiling, critical academic reading, lexical difficulty, lexical diversity, Measure of Textual Lexical Diversity (MTLD). Cite as: Aziz, A., Syed Ahmad, T. S. A., Awang, S., Abdul Aziz, R., Azlan, N. A., & Ahmad, S. N. (2026). Lexical diversity and CEFR vocabulary in critical academic reading passages: A conceptual replication. Journal of Nusantara Studies, 11(2), 228-242. https://dx.doi.org/10.24200/jonus.vol11iss2pp228-242