I worked at a Chinese restaurant for some years, and my boss natively spoke Mandarin but whenever he was muttering to himself about something or another he would always cuss in English. I have no idea why this should be but it was always hilarious.

Similar situation in South Tyrol (an province at the border to Austria): the german-speaking minority (who is the majority in the province) primarily uses italian curse words. A theory I once read trying to explain this is that you hope that God is less likely to notice you when you curse in a different language.

As a regular Swede I will say that Finnish swear words hit differently. More oomph in them xD

I'm German and I also sometimes use perkele, just because it's such an awesome word. Don't know about my pronunciation though...

Tbf I also do that, but my grandma was Finnish.