For Indonesia, language is not only a tool for communication, but also a symbol of national unity, a reflection of the establishment of the Republic of Indonesia, the diversity of ethnic groups, and the parameters of the nation's competitiveness internationally. Within the framework of the nation, there are three principles of languages called Trigatra Bahasa, which is expressed through Indonesian, local, and foreign languages. This study is aimed at establishing a Trigatra Bahasa learning model based on 21st century skills. The high school language teacher's role encompasses not just imparting spelling and grammar to students but also facilitating comprehension of Trigatra Bahasa, a national unification principle. Sadly, few teachers have explored critical theories and philosophies concerning this essential matter, mainly on the account of the absence of comprehensive language curricula showcasing the Trigatra Bahasa spirit as a national language policy. This study employed the Research and Development (R&D) approach of the 4D model, consisting of four phases: Definition (Define), Design (Design), Development (Develop), and Dissemination (Disseminate). The research focused on a learning device model which underwent the initial stages of Definition and Design, followed by the subsequent Development and Dissemination phases. The participating schools were SMAN 8 Cirebon, SMAN 2 Cibinong, and SMAN 3 Tasikmalaya. The data collection tools comprised questionnaires, observations, interviews, and tests. The questionnaire tool was dispensed to teachers and grade X high school learners for gathering information on language learning needs, the use of learning media, and other factual data. The observation tool facilitated monitoring of the language learning process in the classroom.