Earth : Europe : Balkans : Bosnia and Herzegovina : Western Srpska
Western Srpska is region in Bosnia and Herzegovina. Includes most part of the Bosnian Krajina (part of which is on the river Vrbas) and Posavina (Bosnian part of which lies along the river Sava)
Dominant language in the region is Serbian. given that the Serbian language has two decrypts, and used both Latin and Cyrillic.