The Balkans were the first sprachbund (linguistic league, area, etc.) identified as a locus of contact-induced change owing to multi-lateral, multi-directional, mutual multilingualism to be identified as such. In this model, multilingualism is shared by speakers of the various languages, it is stable across generations, and it involves varied social groups. While no linguistic situation is unchanging, the combination of the factors mentioned here differentiates the sprachbund from other contact situations such as a diaspora, a colony, or that of endangered indigenous languages. Owing to the complexity of a sprachbund, the directionality of contact-induced change is not always discernible, nor is such directionality necessarily relevant, the point being the fact of convergence itself. This chapter defines the basic linguistic features relevant to the study of the Balkans as a linguistic area and also gives an overview of the linguistic study of the region. An important conclusion is the fact that the Balkan sprachbund continues to be a relevant lens through which language contact – both historical and ongoing – can be viewed.