International mobility has significantly increased the linguistic and cultural diversity within our schools. So much so that currently one of the main roles of school is the linguistic capitalization of the new generations. Thus, the European Commission defends an education that promotes multilingualism among students. A multilingualism that takes into account regional minority languages, languages that come from migration and foreign languages. In this sense, bilingual education models, assessment of the knowledge of the school language(s), linguistic transfer processes, linguistic error analysis during language learning, and successful teaching and learning methods have become the main axis of our research.