Although dynamic assessment (DA) has shown promise in fostering interlanguage pragmatic (ILP) competence, empirical comparisons of concurrent and cumulative group dynamic assess-ment (G-DA) remain limited, particularly regarding speech act production across proficiency levels using microgenetic analysis. However, no study to date has simultaneously compared concurrent and cumulative G-DA in the production of requests, refusals, and compliment re-sponses across three proficiency levels while tracing the moment-to-moment microgenesis of ILP development. This explanatory sequential mixed-methods study addresses these gaps by investigating the efficacy of concurrent and cumulative G-DA in enhancing the ILP competence of Iranian English-as-a-foreign-language (EFL) learners at the pre-intermediate, intermediate, and upper-intermediate levels, focusing on requests, refusals, and compliment responses (CRs). To this end, 90 Iranian EFL learners were randomly assigned to nine groups (10 learners each): three concurrent G-DA groups (n = 30), three cumulative G-DA groups (n = 30), and three con-trol (non-GDA) groups (n = 30), with each condition including learners from all three proficien-cy levels. MANOVA, one-way ANOVA, and Scheffé post hoc tests revealed significant im-provements in both G-DA groups compared to the non-GDA groups (p < 0.05). Concurrent G-DA yielded superior outcomes, particularly among pre-intermediate learners, followed by in-termediate learners; gains were smaller at the upper-intermediate levels, suggesting a ceiling effect. Microgenetic analyses of audio-recorded collaborative dialogues further illustrated how dialogic mediation in concurrent G-DA promoted greater pragmatic awareness and self-regulation, whereas cumulative G-DA provided more structured support suited to lower-proficiency learners. The findings underscore the necessity of matching mediation type to learners’ proficiency levels to optimize ILP development.
