Government initiatives for strengthening the safety of the United States led to increased requirements for military linguists' knowledge of foreign languages. This study explored the development of professional training for instructors at a military language school to address the gap in teaching services. The purpose of this single case study was to explore best teaching practices for engaging adult students' foreign language learning following andragogical principles. Knowles's theory of andragogy provided the conceptual framework. Data were collected using anonymous responses to an online survey from 26 instructors who answered 3 open-ended questions. Data were analyzed by coding answers to the research question and indicated that approximately one third of participants preferred language-centered practices for engaging their students' foreign language learning. Another third of the respondents noted learner-centered approaches, and the remainder listed both language- and learner-centered approaches among best teaching practices. The proposed curriculum might facilitate discussion about the benefits of each approach to promote teaching and learning at the site. Participating in suggested training that is grounded in the theory of andragogy and local data may bring about positive change by advancing instructors' expertise, improving educational services, and resulting in increased students' proficiency.