This chapter provides two-way immersion (TWI) in general and in Berlin in particular, and looks at the institutionalization process of TWI programs and school innovation more generally. As regards the migrant orientation, the documents refer to the international population in Berlin, namely migrants from former Yugoslavia, Turkey, and Poland, and to "the implementation of the right to mother tongue education for migrants in this city". Initially, TWI instruction was possible based on existing national curricula that provided for the introduction of a first foreign language in Year 1 and a second in Year 5. The documents suggest that the existing legal situation was a facilitating factor in the implementation phase. However, in order to enable State Europe School Berlin to function effectively and sustainably, the legal basis needed adapting, which required authorities to take note and work out solutions. The chapter concludes by suggesting factors that may indeed facilitate or hinder the institutionalization process.