Collaborative writing (CW) and written corrective feedback (WCF) offer benefits in error processing and language development. This study explores their combined advantages through written languaging (WL) for 202 fourteen-year-old EFL learners. To explore the effects of WL processing, participants were allocated to six groups with distinct writing and processing conditions: (1) individual writing and error processing (I-I), (2) collaborative writing and error processing (C–C), (3) individual writing and collaborative error processing (I-C), (4) collaborative writing and individual error processing (C-I), and two control groups who wrote (5) individually (I-CG) and (6) collaboratively (C-CG) and did not process WCF through WL. The analysis focused on accuracy and correction rates across four texts (pre, rewritten, post, and delayed). Results unveiled immediate and prolonged advantages of WL processing, demonstrating that students processing WCF through WL significantly enhanced accuracy and error correction rates in rewritten texts compared to controls. Moreover, both individual processing groups (C-I and I-I) proved more effective than collaborative processing groups (C-C or I-C) for correction and accuracy rates, with I-I exhibiting the best outcomes. This study highlights the immediate and prolonged advantages brought about by integrating CW and WCF through WL, offering valuable insights for optimizing language learning practices.