This study investigated the comparative efficacy of Communicative Language Teaching (CLT) and Task-Based Language Teaching (TBLT) in second language (L2) acquisition, treating TBLT as a task-based operationalization of CLT principles rather than a wholly competing approach. A mixed-methods quasi-experimental design compared 60 intermediate L2 learners enrolled in two pre-existing classes at a higher-education institution in Ahvaz, Iran, with one class taught using CLT and the other using TBLT over a 12-week intervention. Data included pre-/post-tests, classroom observations, and questionnaires. Within-group gains were significant for oral proficiency and task completion in the TBLT group and for grammatical accuracy and interactional competence in the CLT group. Direct between-group comparisons showed that the TBLT group scored significantly higher than the CLT group on oral proficiency and task completion, whereas the CLT group scored significantly higher on grammatical accuracy and interactional competence. Neither group showed significant vocabulary gains. Because the design did not include a no-treatment control group, these gains could not, on their own, be attributed solely to either method. Qualitatively, CLT learners reported higher engagement, whereas TBLT learners reported greater autonomy; 40% of TBLT learners reported frustration with reduced attention to grammatical form. Learners’ proficiency level and cultural background appeared to correspond with how each approach was experienced, although these relationships were not formally tested. The findings were consistent with a domain-specific pattern of relative strengths for CLT and TBLT. A blended instructional approach was proposed as a direction for future research efforts rather than a conclusion established by the present data.
