“…In response, the present study seeks to address this gap by examining EFL learners' lexical complexity in their oral English. Although lexical complexity can be investigated through various aspects such as diversity, density and sophistication (Skehan, 2003;Bulté and Housen, 2012), complexity is primarily shaped by lexical diversity, and operationally, lexical diversity is usually the most frequently used measure for assessing lexical complexity (e.g., Ågren et al, 2012;Han et al, 2021) and lexical development (e.g., Crossley et al, 2009). In the current study, therefore, as has been the case for most studies so far, complexity is quantified using lexical diversity in the tripartite CAF framework.…”