This study examines the outcomes of a US-based six-week summer professional development program for 19 Taiwanese teachers of Mandarin Chinese as a Foreign Language. The goal of this funded program was to facilitate international teachers' understanding and application of the "World-Readiness Standards" for Learning Languages (National Standards Collaborative Board, 2015) and implementation of interactive pedagogical practices into their teaching practice; it also sought to promote learner-directed, proficiency-oriented classrooms with interactive and engaged learning and authentic language development for their learners. The current study examines the learning that occurred for participants during the professional development program. Data showed that at the outset of the program, while participants may have heard of student-centered instruction and the "World-Readiness Standards for Learning Languages" (National Standards Collaborative Board, 2015) and of the ACTFL/CAEP "Program Standards for the Preparation of Foreign Language Teachers" (National Standards for Foreign Language Education Project [NSFLEP], 2013), they were not aware of the standards' actual implementation in classrooms or how these applied to themselves as educators. Analysis of participants' pre- and post-program surveys and professional electronic portfolios provided evidence of the ways in which participants "lived" the standards to increase their knowledge of them. These data also provided evidence of how important it was for participants to experience the standards as learners to support their growing understanding of new teaching practices, learner-directed instruction, and international mindedness. The researchers utilized a critical stance to explore the Taiwanese teachers' professional and cultural learning, as well as their own learning as facilitators and instructors in the program. Results suggest that international teacher candidates may benefit from, and even require, more in-depth work to help them deeply understand and be able to apply the standards that lead our profession. While all teacher candidates might benefit from an active learning approach to better understand the standards and be able to apply them actively in their teaching practice, it was in the "lived" experiences of interacting with the sets of standards as both learners and future teachers that enabled the international candidates to ultimately grasp their meaning and be able to apply them in their foreign/world language lesson planning. Reflection proved to play a core role in their growth as future educators.