There are actually rules (for most words), but since no one knows them, no one teaches them either haha. French is my first language and I only discovered said rules past my twenties.
When I first started actively speaking english, I used to mix up phrasal verbs. Once, as I was talking with an American, I said "and so, she drank it down in one go and passed away on the sofa HAHAHAHA" while laughing, instead of "pass out", and I still remember the poor man's frozen look.