That language plays a pivotal and integral role in making political processes participatory and inclusive, and socioeconomic development sustainable has been commonsensically presumed to be a well-established fact. Language is not simply a means of mutual communication, but also a potent tool for social inclusion and exclusion, resulting in having both a positive and negative social impact. In this sense the use of African languages in all social domains for making sure of the concretization of inclusive political participation and representation as well as sustainable socioeconomic development. Despite being considered to be an exemplary country that has pursued an active endoglosic language policy, Tanzania has an uphill task in facilitating participatory democracy and sustainable socioeconomic development by virtue of the ease of language understanding with which people can make them understood in everyday life. What is imperatively needed in making participatory democracy and sustainable socioeconomic development possible and feasible is a strong political will and its implementation. In tandem with a strong political will and its implementation in the conduct of national affairs, a ceaseless and concerted effort needs to be made with a view to capacitating Swahili to make a meaningful contribution to participatory democracy and sustainable socioeconomic development. Furthermore, corpus planning that refers to an institutional effort for creating standards for Swahili has to be done.