in english we've got a saying as well. "SHUT THE **** UP!"
Hm, It's not exactly the same meaning, but still it's one of my favourites. If I would have gotten a dollar for everytime I used it, I sure would have heaps of dollars
I would even add someting to that phrase:
If you don't know what you're talking about, shut the f*** up!
Or maybe even the quote the movie "The big Lebowski":
"Shut up, Donny, you're out of your element!"