As an Italian-American who rarely gets to speak Italian, my visits to my family in Italy are full of these kinds of things, but in the other direction, naturally.

I end up using less common, typically larger words mostly because they have direct equivalents in English, including a whole bunch that end in -ation, which in Italian typically end in -azione.

My relatives joke with me that I'm a weird, overeducated dummy who "knows" these big words but doesn't know basic idioms.