Don't be afraid to just talk. Sounds counter-intuitive I know, but don't try and translate, just assume you know what she's saying, read her body language, and chat back in german, english, french, whatever.
It's actually a lot of fun and you can have a really long conversation that will surprise you with its duration.
I first took this up at a sidewalk lunch spot in Saigon. An old guy started chatting to me and I just answered him back with whatever I thought we were talking about. Went on for 30 minutes, it was kind of a "Lost In Translation" moment. Ended up trying it with the karaoke girls and it worked there to!
