Chakavian
Chakavian in its actual use is the least spoken Serbo-Croatian dialect, being spoken only by 12% Croats. It is now mostly reduced in southwestern Croatia along the eastern Adriatic: Adriatic islands, and sporadically in the mainland coast, with rare inland enclaves up to central Croatia, and minor enclaves in Austria and Montenegro. All areas of old contacts with Romance languages.
Vlachs in the history of Croatia
Socioculturally, there were two main ethnic divisions in the Croatian Military Frontier, those of the "native" "Croats" and "immigrant" "Vlachs". The Croats were Catholics, Habsburg subjects, made up of an agrarian population concentrated around frontier towns, of nuclear families, and linguistically predominantly Chakavian-speaking (or Chakavian-based speech). The Vlachs were holders of patriarchal-pastoral culture of the Dinaric, refugees from Ottoman and Venetian territories, of extended families, and linguistically Neo-Shtokavian-speaking.