Examining the Role of Lexical Sophistication, Lexical Diversity, Syntactic Sophistication, Syntactic Complexity, and Cohesion in L۲ Speaking Proficiency Assessment

AbstractThe present study developed a model of L۲ speaking proficiency investigating how lexical sophistication, lexical diversity, syntactic sophistication, syntactic complexity, and cohesion are associated with holistic scores of L۲ speaking proficiency employing structural equation modeling (SEM). A corpus of ۴۱۹ monologues delivered by Iranian EFL learners was compiled and rated to develop the model. Based on the overall scores, the corpus was divided into independent (B۱ and B۲) and proficient (C۱ and C۲) users. The results of SEM analysis revealed that the developed L۲ speaking proficiency model had an acceptable fit, with partial generalizability across independent and proficient users. Structural regression analysis showed that lexical diversity, lexical sophistication, syntactic sophistication, cohesion, and the indirect effect of syntactic complexity through lexical sophistication explained ۳۴% of the variance in L۲ speaking proficiency in descending order of importance. However, their relative importance changed depending on proficiency level. Based on the results, while lexical, syntactic, and cohesive features are sound predictors of L۲ speaking proficiency, they function differently across proficiency groups. These findings offer valuable insights for improving speaking proficiency assessment by showing that lexical sophistication, lexical diversity, syntactic sophistication, syntactic complexity, and cohesion do not contribute equally to overall L۲ speaking proficiency, and their order of importance varies across proficiency levels. Therefore, prioritizing indicators of L۲ speaking proficiency in assessment frameworks based on their importance in each proficiency level can add to the validity and reliability of speaking assessments.

کلیدواژه ها:

cohesion ، L۲ speech assessment ، lexis ، syntax