The concept of Sustainable Development (SD) is gaining grounds in developmental discourses, given that it is the 2030 universal agenda of the UN. Harlem Brundtland, pioneer Chair of the World Commission on Environment and Development, defines SD as “development that meets the needs of the current generation without compromising the ability of future generation to meet their own needs” (Mensah, 2019, p. 7). In this global seventeen-agenda that advocates prosperity in countries, goals #4 (Quality education), #10 (Reduced inequalities), #13 (Climate action), #14 (Life below water), #15 (Life on land), #16 (Peace, justice and strong institutions) and #17 (Partnership for the goal) hinge on the importance of language in enhancing national development. This paper studies the current practice of official bilingualism in the Cameroonian bilingual university and local councils, notably the effective and equitable use of English with French, and their impact on SD in the country. To verify the developmental potentials which the current English Language practice offers Cameroonians, the mixed method was used. This included questionnaires and observations that were respectively administered to 250 students of the University of Yaounde 1 and 04 municipal councils in Yaounde. In addition to the manual method, the questionnaires were complemented by Google Forms. The Capability Approach, also referred to as the Human Development Approach, was the language policy framework used to analyse the effectiveness and adequacy of current English Language governance tools and practices in Cameroon, and the role they play in the attainment of the Sustainable Development Goals. Findings have it that current language governance tools are inadequate and unproductive, and the current English Language practice in all official domains is ineffective. Bearing in mind that English is the lingua franca of international cooperation and communication (in the domains of education, politics, trade, and the media) and above all, the default language of modern science and technology, it was observed that the timid practice of English in Cameroon hampers national development; Cameroonians are being shaded from international development opportunities (like scholarships, training, employment, and partnership and funding programs, and scientific and technological knowledge and opportunities) in English. English being a tool of international peace, education, adaptation and cooperation, it is recommended that authorities should put in place effective and efficient English Language policy instruments that would attend to the developmental needs of Cameroonians.