Lexical Diversity and Grammatical Complexity: On Their Relationship with Language Proficiency in Writing

Abstract

Purpose: This study aims to explore the relationship between lexical density, grammatical complexity, and language proficiency in the writing of Iraqi EFL learners, addressing a gap in cross-sectional research on these linguistic features. Design/Methodology/Approach: A total of 22 Iraqi EFL learners participated voluntarily in the study. Each participant produced a writing sample based on IELTS Task 2 (argumentative essay). The samples were rated by two experienced EFL instructors. Lexical density and grammatical complexity were analyzed using Textalyser software, and the data were statistically examined using SPSS version 25 through correlational analyses and multiple regression. Findings: The results revealed a significant positive correlation between lexical density and writing proficiency, suggesting that lexical richness contributes to better writing performance. However, multiple regression analysis indicated that grammatical complexity served as a stronger predictor of writing proficiency than lexical density. Conclusion: While both lexical and grammatical features play important roles in writing proficiency, grammatical complexity appears to be a more critical factor in predicting EFL learners’ writing performance. Practical Implications: The findings highlight the need for language instruction to place greater emphasis on the development of grammatical complexity alongside lexical diversity. Pedagogical strategies targeting these areas may enhance learners' overall writing proficiency and academic success in English.