Luxembourg maintains by far the largest proportion of foreign immigrants in Europe. This is also reflected in the population of children. About 50% of children under the age of four are foreign nationals. Accordingly, the question of how to deal with linguistic diversity represents one of the biggest challenges in the professional debate about early childhood education in Luxembourg. The article will refer to this issue on the basis of several insights stemming from an ethnographic study in Luxembourgish daycare centers which was conducted between 2009 and 2012 by the working group Early Childhood: Education and Care at the University of Luxembourg. The study explored practices professionals apply to come up with the superdiverse and translingual environment in order to meet the political expectation of promoting foreign children’s competences before they enter school. Based on the empirical investigations of everyday language use in center-based early childhood education, the article will not only characterize two different modes of language promotion (institutional monolingualization in one language and institutional monolingualization in several languages) but also highlight the ambiguities of those language promotion practices which, although facing a translingual environment, are still based on a multilingual standard.