My wife and I both took German in high school and were taught by a native German. He told us the way that Germans count one with their thumb instead of with their fore finger. I always remembered this and she didn't.

While watching *Inglourious Basterds* I noticed the slip up right away she had no idea until after the shooting stopped and it was explained  on screen. As Christian Rau it's one of those small cultural differences that aren't always noticed or commented on even when surrounded another culture. 

What's stranger to me in that scene is the Nazi jumps automatically to these are enemy soldiers due to such a small cue.