I concur with all the above. I currently live in Sweden (from USA/Louisiana) and while a good portion of the younger (15 - 30) year old's understand basic English, but they aren't exactly fluent. Then when you meet people in the (50 - 70) year old range there is a sharp drop-off in their English completely.
However, I have found no problems with performing magic for any age group as long as you keep it very visual.
About 2 weeks ago my girlfriend and I were visiting her brother outside the Hotel he was staying at, just talking a bit, having a cigarette. I started doing a few cigarette vanishes/flourishes for him and about that time, an older gentleman whom I would say was around 70 who couldn't speak any English walked up as I was producing a recently vanished cigarette with a big smile upon his face.
Apparently, he had been watching me for a few minutes before hand.
I asked, "Would you like to see some card magic?" (my girlfriend doing the translating) He nodded yes and so I pulled out a deck of cards from my back pocket and showed him an Ambitious card routine which included Marc Desouza's "Shape Shifter" effect for the final reveal to that routine, and the super easy "Erdnase color change", and this man was completely blown away.
Keep it simple, keep it visual, and you'll do just fine.
Best of luck,
- Steve