This study aimed to enhance student engagement in language classrooms by developing a professional learning community (PLC) in the Modern Language Department in a high school. This exploratory study uses a mixed-method design collecting both quantitative and qualitative data through various instruments. Incorporating improvement science, the teachers engaged in an 8-week plan-do-study-act cycle to learn and share instructional practices focusing on student-centered strategies. This study aimed to understand: (1) How do teachers engage in a PLC? (2) How do teachers describe their learning of new instructional practices and strategies and apply what they have learned in their classes? (3) How do students and teachers identify and describe any changes in student engagement after teachers implemented what they learned from the PLC? The methodology included a pre-PLC survey, teacher interviews, exit tickets for PLC meetings, meeting notes, and pre- and post-student surveys on the song project intervention. The findings revealed that veteran teachers could learn and develop knowledge and skills by sharing and discussing with each other within the structured time and space provided by the PLC. Student engagement was enhanced as the teachers used student-centered instructional practice they learned from the PLC. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]