ORIGINAL RESEARCH article
Front. Educ.
Sec. Higher Education
Volume 10 - 2025 | doi: 10.3389/feduc.2025.1616935
Lexical Diversity, Syntactic Complexity, and Readability: A Corpus-Based Analysis of ChatGPT and L2 Student Essays
Provisionally accepted
Daniel Fredrick*
LAURENCE CRAVEN- American University of Sharjah, Sharjah, United Arab Emirates
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This study compares AI-generated texts (via ChatGPT) and student-written essays in terms of lexical diversity, syntactic complexity, and readability. Grounded in Communication Theory—especially Grice's Cooperative Principle and Relevance Theory—the research investigates how well AI-generated content aligns with human norms of cooperative communication. Using a corpus of 50 student essays and 50 AI-generated texts, the study applies measures such as Type-Token Ratio (TTR), Mean Length of T-Unit (MLT), and readability indices like Flesch-Kincaid and Gunning-Fog. Results indicate that while ChatGPT produces texts with greater lexical diversity and syntactic complexity, its output tends to be less readable and often falls short in communicative appropriateness. These findings carry important implications for educators seeking to integrate AI tools into writing instruction, particularly for second-language (L2) learners. The study concludes by calling for improvements to AI systems that would better balance linguistic complexity with clarity and accessibility.
Keywords: AI-Generated Writing, linguistic complexity, L2, Grice's Cooperative Principle, Readability analysis
Received: 23 Apr 2025; Accepted: 01 Sep 2025.
Copyright: © 2025 Fredrick and CRAVEN. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Daniel Fredrick, American University of Sharjah, Sharjah, United Arab Emirates
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