Wikipedia
Kajkavian (Kajkavian noun: kajkavščina; Shtokavian adjective: kajkavski , noun: kajkavica or kajkavština ) is a dialect of the Croatian language spoken by Croats in Central Croatia, Gorski Kotar and northern Istria. It has low mutual intelligibility with the Shtokavian, on which Croatia's standard language is based. Some notable linguists consider Kajkavian to be a language of its own. As of 2015, Literary Kajkavian has a separate language ISO 639-3 code – kjv. Active attempts are being made by some organizations to widen its recognition and status, which has thus far included introduction of school subjects in Kajkavian in some parts of Croatia as well as the creation of the aforementioned ISO code.
The term Kajkavian stems from the interrogative pronoun kaj (what). The other main dialects of Serbo-Croatian also derive their name from their reflex of the interrogative pronoun. However, the pronouns are only general pointers and do not serve as actual identifiers of the respective dialects. Certain Kajkavian dialects use the interrogative pronoun ča, the one that is usually used in Chakavian. The pronouns these dialects are named after are merely the most common one in that dialect.
Outside Croatia the dialect is also spoken in Austrian Burgenland and a number of enclaves in Hungary along the Austrian and Croatian border and in Romania. Although speakers of Kajkavian are Croats, and Kajkavian is considered a dialect of Serbo-Croatian, its closest relative is the Slovene language, followed by Chakavian and then Shtokavian. Kajkavian is part of a dialect continuum with both Slovene and Chakavian.