CJAL * RCLA Birello, Comajoan-Colom?, &amp; Salguero i Written corrective feedback in L1 and L2 in higher education: An international perspective Introduction Marilisa Birello Universitat Aut?noma de Barcelona Lloren? Comajoan-Colom? Universitat de Vic-Universitat Central de Catalunya Tania Salguero Universitat Aut?noma de Barcelona Research on written corrective feedback (WCF) has become central to our understanding of how writing skills develop and how language learners respond to instruction. As writing instruction shifts toward more student-centered, process-oriented approaches, the need to examine how learners interpret, engage with, and apply feedback has grown. WCF research provides insights into these processes and contributes not only to second language acquisition theory but also to improvements in writing pedagogy across diverse contexts. This special issue brings together a selection of peer-reviewed papers originally presented at the 1st International Conference on Written Corrective Feedback in L1 and L2, held at the Universitat de Vic-Universitat Central de Catalunya (UVic-UCC) in 2023 (www.wcf23.org). The conference was organized by the Glossa research group of the Universitat de Vic-Universitat Central de Catalunya, with the collaboration of the Elbec research group of the Universitat Aut?noma de Barcelona. It was funded by the projects "Mestres i retroacci? correctiva escrita/Teachers and written corrective feedback" (2020ARMIF 0025, Secretariat of Universities and Research, Generalitat de Catalunya) and PIRE2021 (CIFE, UVic-UCC) and a grant for the organization of activities in scientific dissemination at UVic-UCC (Vice-Rectorate for Research and Knowledge Transfer). The conference aimed to foster dialogue between researchers and educators engaged in understanding how feedback practices can shape writing development across educational contexts and linguistic backgrounds. The five contributions in this issue reflect the diversity and depth of that dialogue and offer empirical insights into feedback practices, learner engagement, and the dynamics of classroom interaction across first and additional language settings. This special issue is structured around three thematic strands that emerged prominently during the conference: learner engagement and feedback processing, instructor practices and feedback effectiveness, and collaborative dimensions of writing and revision. The volume opens with a foreword by Rosa Manch?n, where she reviews developments in WCF research, focusing on learner engagement and contextual variables and how they contribute substantively and methodologically to the field across L1 and L2 contexts. The first study, The differential effect of individual and collaborative processing of written corrective feedback on French as a foreign language learners' engagement, is authored by Lira-Gonzales, Nassaji, and Chao and investigates how learners of French Canadian Journal of Applied Linguistics: Special Issue, 28, 1 (2025): i-ii CJAL * RCLA Birello, Comajoan-Colom?, &amp; Salguero ii as a foreign language engage with written corrective feedback when processing it individually versus collaboratively. Through a mixed-methods design, the authors identify differential patterns of cognitive, behavioral, and affective engagement, and offer evidence for the pedagogical potential of collaborative feedback interpretation. This focus on engagement continues in Michaud, McDonough, and Parent's article titled The impact of timing in written corrective feedback on collaborative writing and L2 accuracy development. The study compares the effects of immediate and delayed feedback during collaborative writing tasks among adult learners of French. Their findings--showing that immediate feedback enhances writing accuracy while delayed feedback encourages metalinguistic reflection--complement Lira-Gonzales et al.'s emphasis on processing depth and provide important implications for task design in L2 classrooms. Transitioning to institutional contexts and teaching practice, Birello, ComajoanColom?, Salguero, and Sorolla, in Written corrective feedback at university: Detection of errors by teachers and impact of different forms of feedback, examine how university instructors detect and respond to errors in student texts in Catalan. Their study contrasts forms of feedback (direct, indirect, metalinguistic) and tracks the extent to which students incorporate this feedback into revised drafts. The data underscore the impact of teacher style and the prevalence of indirect feedback, while confirming high uptake rates. The issue moves to a comparative perspective in the study titled A comparison of EFL students and instructors' written feedback preferences and reported practices at a Moroccan university, by Mamad and V?gh. By examining alignment (or misalignment) between reported practices and preferences, the authors draw attention to the importance of mutual expectations and shared understanding of feedback purposes in L2 settings. Bea Reyes and Rodr?guez-Gonzalo, in Collaboration in the revision of a piece of writing: An analysis of group revision sessions with university students, analyze collaborative revision sessions in Spanish university classrooms. Their case study sheds light on how group revision fosters students' meta-rhetorical and metalinguistic awareness when writing biographical texts. The study positions revision not as superficial correction, but as a recursive and developmental process, echoing themes of student agency and dialogic learning. Finally, the special issue concludes with an epilogue by Hossein Nassaji and Eva Kartchava, who reflect on the evolving role of WCF as a dialogic process shaped by both teacher instruction and learner agency and provide avenues for further research. Taken together, the articles in this volume illustrate the ongoing evolution of feedback research and practice and highlight the complexity of feedback as a situated, social, and cognitively demanding practice. We hope that readers will find in these contributions both a resource and an invitation to refine the ways feedback is conceptualized and implemented in writing instruction. We thank all the anonymous reviewers who reviewed the studies and particularly Rosa Manch?n, Eva Kartchava, and Hossein Nassaji for writing the foreword and epilogue, respectively, and for their ongoing support. Canadian Journal of Applied Linguistics: Special Issue, 28, 1 (2025): i-ii