I've been doing SWE for 10+ years in Poland and I encountered non-English language in code precisely once - in a German project, lol. Some guys do leave Polish comments here and there, or in commit messages or in other docs/jira tickets/whatever - but in db schema, variables, properties, methods etc? Never, ever. English is 100% a requirement for every developer job offer I've ever encountered in Poland. Not necessarily a very high level for programmers (if you don't speak directly with the client), but you wouldn't get an offer at all if you're very far below B1.

I mean we're kind of an outsourcing hub so it makes sense. Even some of our companies outsource further to the east so you really can't avoid it.