The effects of task complexity and task repetition on sense-aware frequency-based lexical sophistication indices in L2 writing

Research on task-based second-language (L2) writing has largely focused on investigating how task complexity (TC) affects various aspects of written production. However, this body of research has rarely examined the effect of task repetition, either on its own or in interaction with TC. Additionally, studies have predominantly used traditional frequency-based measures of lexical sophistication, without incorporating more nuanced, sense-aware indices that could offer a deeper understanding of linguistic complexity. This study aims to explore and compare the impact of TC, task repetition, and their interaction on lexical sophistication in L2 writing, using both traditional and sense-aware frequency-based indices. Ninety-six participants completed two argumentative essays on simple and complex tasks in counterbalanced order, twice over four weeks. These essays were analyzed using a set of lexical sophistication indices, both traditional and sense-aware. Repeated-measures MANOVA with TC and time as within-subject variables showed significant main effects of TC and time on overall lexical sophistication, with sense-aware indices being more sensitive and yielding larger effect sizes than traditional word-form-based measures. The theoretical, methodological, and practical implications of our findings are discussed.