This paper argues that learning in an unfamiliar language of learning and teaching (LoLT) negatively impacts Rwandan girls in the early years of lower secondary education. Based on classroom observation and interviews with case-study girls in four Rwandan secondary schools, we show that where girls' life circumstances differ, so too does the way in which the use of an unfamiliar LoLT affects them. Through the development of five typologies, we explore the ways that when girls face inequalities at the levels of time, space, material and emotional support they have for learning, the requirement that education be conducted and assessed in an unfamiliar language works to compound these inequalities. Our conclusions advocate for greater attention to be paid to the language of learning and teaching in global and national girls' education policies to alleviate the 'double burden' that many girls carry.