It sounds like some kind of mixture between Slovenian, Serbo-croatian and Polish. I personaly belive Sorbian is closest to proto-slavic you can get becouse they were so isolated from other Slavic nations. I was always interesed in Sorbs becouse they are only one besides Slovenes who still use complete grammatical dual.
It is clear to me that these young kids speak Sorbian with strong german accent like Carinthian Slovenes. Thats becouse they speak german language in public and with friends. But i am glad that they are learning Sorbian.