We also have a lot of Dutch guys. They didnīt speak german that fluently in the beginning, but as the languages are quite similar, it didnīt take so long.. (but they are eager to maintain that dutch accent, because our girls in Germany go crazy for that!)
Then a couple of years ago we had a lot of Spanish collegues, but they all returned to Iberia after a while (pay wasnīt good enough)..
And I think 10 to 15 years ago there were a lot of British pilots working on the 737 fleet (right side)..
I guess a 6 months crash course in german wouldnīt be a bad idea.
Rgds