Changing language of Instruction was a policy decision taken to reverse the process of Arabicization of the South by the Northern Arab Sudanese that was ongoing throughout the war period. This minor field study that took place in a school in Southern Sudan was to investigate the challenges of this change on teaching and learning. The research investigated how teachers and learners are coping with the change, how the policy is being implemented, the gaps and mismatches between the policy intentions and its implementation and relating the effects of all these on teaching and learning from pedagogical and linguistic points of view. The study shows that most teachers in the research paradigm understood little English because most of them were trained in Arabic. The change from Arabic to English was announced but the teachers had hardly any training in English thus a gap between policy and implementation. The research also established that due to the inadequate language proficiency the teachers struggle to teach in English albeit have ambiguous opinions concerning the policy.