In this article I argue that language policies for education have effects on pupils’ educational possibilities. With the case of Karagwe district in Tanzania I have found that the case of “Swahili only” in primary school education favours the small minority of the children that live in a context where Swahili is used. This leads to inequality in pupils’ chances in education and to a low level of achievement of academic content in schools. This also promote the developing and use of safety strategies among teachers and pupils that hide failure and prevent pupils’ learning.