technically my first language is english, but i also grew up speaking portuguese and spanish.
although people say i speak portuguese better, i see the advantage that i can communicate with most of the americas. (except for those who don’t speak either language or canadians who only know French)
Potentially Germany, where I grew up we said “Two idiots - one thought”. We have quite a lot if regional variety in these things.
My personal experience is that I just translate one idiom from one language / culture to the other without realising and still expect ppl. to know what I mean.
That often works in my experience, and can lead to funny moments
Hands down my favorite part of interacting with multilingual/multicultural people.
My boss is Romanian, I’m american, we live in Norway, and speak English with one another at work (Norwegian to customers).
She uses the phrase “running around like a headless chicken” often and I’ll never tell her that I heard the longer “running around like a chicken with their head cut off” version of this, especially in the south, as a kid. I like hers more.