Hi smooth
The tech test is in english so no prob. The psycometrics can be done in english if you rerquire. But then there is the issue of the group discussion and the interview where it will pose a problem. There were loads of dutchies there last year so obviously cant be too much of a hurdle.
My dads german, so lucky for me im fluent.
Get test training 2000 by hesse and schrader from
www.amazon.de, and do the tests for pilot selection and also get an faa com study guide, this helped allot.
cheers and good luck