The relatively recent phenomenon of rapidly increasing migration flows in multiple forms and channels has been termed superdiversity (Vertovec 2007). The resulting new social constellations see an increase in the amount and types of language proficiencies, particularly in large urban areas. Linguistic diversity per se is not a new phenomenon, yet education systems continue to respond to this diversity with the construct of the monolingual habitus (Gogolin 1994) that associates a single language with one nation. National education systems interlace mono- and multilingual features, displaying monolingual self conceptions in their constitutions, structures and practical arrangements on the one hand, and a multilingual student body on the other. Moreover, European education policies show a frustrating facet of this phenomenon. The Council of the European Barcelona objective of 2002, for example, promotes that every child in Europe learns two foreign languages from an early age (Union 2009). At the same time, member states who adopted this document insist on their monolingual mainstream school systems with sections devoted to foreign language teaching, and exceptional provisions for other autochthonous languages on the nation’s territory. Such a system does not cater for the needs of speakers in superdiverse constellations. This contribution begins with an overview of the concept of superdiversity, particularly focusing on issues of linguistic superdiversity. It provides a summary of research topics, as well as methodological issues. Consequences for traditionally monolingual education systems will then be highlighted. The paper will then draw an example of monolingual thinking in a bilingual context before the introduction to the volume.