Exploring English Language Learners’ Vocabulary Knowledge and Usage When Speaking

Abstract

Vocabulary forms a fundamental component of speaking ability, as it enables speakers to convey meaning accurately, fluently, and effectively. Although the relationship between vocabulary and speaking has been investigated to some extent, gaps remain in understanding the link between learners’ vocabulary knowledge and their speaking proficiency, as well as how they deploy that knowledge in speaking performance. Drawing on speech production models, the present study examined the relationship between English as a Foreign Language (EFL) learners’ vocabulary size knowledge and their speaking proficiency, as measured via a speaking task, and further investigated the extent of lexical richness in their speech. The results revealed a clear pattern in the contribution of vocabulary size knowledge to speaking proficiency, with aural vocabulary size showing the strongest predictive power. Findings further indicated that lexical diversity and sophistication emerged as important indicators. Overall, the findings suggested that speaking proficiency depends not only on the quantity of vocabulary knowledge, but also on how flexibly learners draw on diverse, semantically nuanced lexical resources. More proficient learners demonstrated the ability to balance diverse, sophisticated words with accessible, high‐frequency words. Implications for vocabulary teaching and speaking assessment are discussed in light of these findings.