If anyone ever wasn't sure about that, here is final proof that Polka was indeed Polish all along. (As yes, Polka means Polish girl in Polish) : r/Hololive
Rosa Chemical - polka 2 (feat. Guè Pequeno, Ernia) || Lyrics Video - YouTube
Polka Vodka Glass 60ml Pastel Assorted x4
Rosa Chemical – polka 2 :-/ Lyrics | Genius Lyrics