Multilingualism is becoming a crucial issue in our society, especially in the European context. Furthermore, research shows that there is a tendency towards raising children with more than one language (Claire 2012). This brings many new aspects to education, theoretical concepts and approaches to multilingualism. Therefore, (multi-)linguists try to illuminate multilingualism from different points of view and try to explore and explain different paths of language development academically. The theoretical part of this thesis will present theories of multilingualism and language complexity....