Processing instruction with structured/unstructured output: Does it make any changes in automatic/non-automatic explicit grammar knowledge?

Research has underscored the separate role of output to promote processing instruction (PI) effects in language learning. Yet, there is a need to scrutinize the interplay between structured output (SO) and unstructured output (USO) within PI to understand how innovative combinations may enhance ultimate educational attainment. The present quasi-experimental study investigated the possible effects of PI with/without SO and USO on learners' short-term and long-term automatic and non-automatic explicit knowledge of English passive structure. A homogeneous sample of 115 Intermediate learners of English as a foreign language (EFL) in intact groups was selected and randomly assigned to four experimental groups (PI, PI+SO, PI+USO, and PI+SO+USO). We administered parallel timed and untimed grammaticality judgment tests (GJT) to measure learning. Kruskal–Wallis, Mann–Whitney, Friedman, and Wilcoxon Signed Rank Tests revealed that the PI+SO+USO group outperformed the other groups. The findings underscore the significance of adding SO and USO to PI in promoting grammar knowledge and offer several pedagogical implications.