Sub-Saharan Africa stands out as a part of the world that relies primarily on the use of non-indigenous languages to act as official (e.g. in the domains of administration, education, law and politics). What explains the overwhelming preference for the colonial language to act as official despite the high costs of obtaining linguistic capital? In this paper, we analyze the role of perceived costs and returns to different languages, the attitudes towards the suitability of non-standardized indigenous languages to be used in formal domains and the importance of ethnolinguistic and class cleavages in influencing individual preferences concerning the choice of the official language. In order to do so we collect data on elicited beliefs about the effects of hypothetical changes to Zambia's language policy on schooling outcomes, income, and social cohesion. Our results show overwhelming support for the use of the colonial language to act as official. Looking at the determinants, we find that fears of being disadvantaged by the installation of another group's language to act as official, high perceived costs of learning in another group's language, and lack of association between retaining the elite language and socioeconomic inequality as crucial factors in affecting preferences over official language.