Not all children attending early childhood education classrooms speak the same first language. What to do when children express themselves in their mother tongue, and not in the language of instruction? If we invest in the first language (i.e., the mother tongue), can we delay learning the language of instruction or, conversely, can we foster the successful development of the two languages? How to respond to immigrant or ethnic minority parents when they ask what they should do at home to promote language development in general or to promote the learning of the language of instruction?