The origins of the 3M project were founded by a range of questions from primary school teachers. They have questions about how they can best manage multilingualism in the education they offer. The province of Fryslân is officially bilingual and teachers in this province acknowledge that not only the appreciation for, but also the use of the mother tongue (Frisian) in school is of great importance for the language development and school performance of Frisian-speaking children. Due to recent forms of migration, more and more pupils, who speak other languages, are coming to Fryslân. As a result, many teachers are not only dealing with pupils who have Dutch and Frisian as their mother tongue, but also with pupils who speak Polish, Arabic or Tigrinya and with many other languages of refugee children who have just arrived in the Netherlands. The teachers are aware of the fact that a good support of language development of all pupils is crucial for high school performance. Teachers also acknowledge that the appreciation and use of a mother tongue should play a major role; but because they do not speak many of those languages themselves, they do not know how to put it into practice. They presented this dilemma to the teachers and researchers at the NHL Stenden University of Applied Sciences. And with this in mind we have started the 3M project that runs between 2017 and 2021.