Language reflects how people think and behave in their culture. To have successful conversations, both language use and cultural awareness should be taken into consideration. Undeniably, Japanese grammar is different from Thai making it even harder for Thai learners to have fluent and appropriate conversations in the Japanese language. In the classroom, typically teachers often focus on grammar, leaving less time for students to practice conversation. Consequently, beginner learners often miss cultural details in conversations and are unable to communicate effectively. Thus, it is important for teachers to immerse students in the Japanese culture to improve their speaking skills and cultural understanding. In so doing, Coordinated Management of Meaning (CMM) and Reader's Theater (RT) were integrated and used to aid beginners in understanding language contexts in order to help users grasp conversational contexts and interlocutors, and use scripted practices to simulate real-life scenarios. This study aims to investigate the impact of an instructional model based on CMM and RT on improving oral communication skills in Thai beginner-level Japanese learners. The study employed an experimental design with 11th-grade Japanese-major students from a secondary school in Bangkok, involving 48 classes over 16 weeks. Instruments included a Japanese oral communication skills test and video-recorded classroom observations. Descriptive statistics, the Wilcoxon signed-rank test were used to analyze quantitative data, and thematic analysis was used to analyze qualitative data. The results showed a significant improvement in post-test scores compared to pre-tests. Moreover, the model has raised students' phonetics awareness. Phonetic features like short and long sounds, pauses, and flapping received more attention. Interestingly, they adapted Japanese pronunciation for Thai or English words enhancing communication with native speakers and avoided using personal pronouns like "anata" opting to address interlocutors by name, adhering to Japanese cultural norms. This instructional model effectively improved both linguistic and cultural competences in Japanese language learners.