Slavs
However, the greatest similarities are between Serbian, Bosnian and Croatian, which are South Slavic languages. They are considered separate by the Bosnian and Croatian governments (the separation is of political nature), but linguistically they are one language- Serbo-Croatian (since Serbian, Croatian, Bosnian and Montenegrin are more similar than those variants of English, German, Dutch, or Hindi–Urdu, and mutual intelligibility between their speakers "exceeds that between the standard variants of English, French, German or Spanish).