Lexical richness in Chinese university students’ EFL writing: a corpus-based comparison

Lexical richness (LR) is widely recognized as a key indicator of proficiency among learners of English as a foreign language (EFL). With the rise of numerous software tools capable of automatically measuring LR in recent years, LR has received increasing attention as a focal area of research in the context of Chinese university students’ (CUSs) EFL writing. However, these quantitative studies often reduce LR to numerical values, lacking a comparative framework for evaluating lexical proficiency in CUSs’ EFL writing. This study adopts Foster and Tavakoli’s approach, using native language proficiency as a comparative baseline. It examines LR in CUSs’ EFL writing compared to English as a native language (ENL) writing, utilizing corpus-based data from SWECCL 2.0 and LOCNESS across three dimensions: lexical density, sophistication, and variation. The results of Mann–Whitney U tests reveal that CUSs’ lexical density in English writing is comparable to that of ENL writing, which may be attributed to the influence of their native language, Chinese. However, they exhibit lower mean ranks of lexical sophistication and variation, showing distinct patterns compared to ENL writing. These disparities may be attributed to factors like limited exposure to advanced vocabulary and cultural attitudes toward risk-taking in language use. Practical pedagogical implications include enhancing exposure to low-frequency vocabulary through enriched input, incorporating contextualized vocabulary instruction, and providing feedback-driven writing tasks that promote lexical variation. This study contributes to the understanding of LR in EFL contexts by emphasizing the need for targeted instructional strategies and offering insights into improving lexical proficiency among EFL learners.