This study examined cross-dialectal Arabic learning and intercultural adaptation among Indonesian students at the Sudanese African Asian School (SAAS), where Formal Arabic (Fusha) and Colloquial Arabic (Amiyyah) were used concurrently in academic and daily communication. The study employed a qualitative case study design anchored in Robert De Keyser's Skill Acquisition Theory and investigated how learners develop linguistic proficiency and navigate sociocultural adjustment within a Sudanese-Arabic environment. Data were collected through observations, semi-structured interviews, and document analysis. Participants comprised the school principal, five Arabic teachers, parents or guardians, and fourth-grade students who were recruited through snowball sampling. The findings revealed that sustained exposure to both varieties supported learners’ grammatical, lexical, and pragmatic competence while facilitating cultural adaptation. Through continuous interaction in authentic contexts, learners developed an understanding of linguistic structures alongside cultural values and communicative norms. This development was supported by cultural immersion, scaffolded instruction, and active learner engagement. However, challenges persisted, including limited Arabic exposure outside school, anxiety in spontaneous communication, and difficulties with unvocalized Arabic texts. The findings suggest that cross-dialectal learning functions as a linguistic and cultural bridge, fostering communicative flexibility and intercultural competence in multilingual Arabic learning contexts.