What nationalities do your languages use as an example of certain behaviour?

İn Czech when somebody is a heavy drinker, we say – “You drink like a Danish”. I actually think that Danish people say “You drink like a Czech” (correct me if I am mistaken). When we don´t understand something we say “this is a Spanish village to me”.

  “To speak double dutch” in English means to say something incomprehensible smile emoticon.
“Why won’t you understand? Are you Turkish?” = Romanian expression for those times when somebody really, really doesn’t get something.

“It’s all Chinese to me.” – this one is for when the Romanian speaker doesn’t understand something. And yes, you can say things like “German truly is Chinese to me.”

In Turkey when someone can’t get the essence of a topic, he/she says “I’m French for this.”
“Am I speaking Hebrew?!” or “Do I sound like I am speaking Latin?!”
usually used in Egypt if someone can’t understand what we said smile emoticon.