No, no, no, that’s fine. Bulgaria is fine. They do the reverse. In their culture, nodding means “no” and shaking your head means “yes.” That’s fine.

Again: they nod for no and shake for yes. It’s actually flipped.

I’m talking about people who think nodding (that is, tilting the head up and down) can be referred to as shaking your head.

Shake goes from side to side. Nod goes up and down. Whatever you mean by each one, that’s a whole separate thing.