If they're isekaid from modern times, why doesn't slang come out more often?

Personally if my ass got isekaid the first thing I would say would be like "oh hell no" or "fuck this" while trying to figure out if the story is one that I can manage to avoid everyone in or even just seeing if I know the story in general. I would be cursing and saying current sayings like crazy, which would make people think I'm insane.

Actually that makes sense as they dont use this age slang, they would be thrown in the basement place forgot the name with the bars well whatever yall know what I'm talking about

Or would end up executed depending on the period. O welp.

It was just one of those AM thoughts that flew through my brain.