BTW, Austria has JAR-FCL licenses now, so conversion shouldn't be a factor.
The company requires that you learn a reasonable amount of german within a reasonable time.
95% of all written documentation and all CBTs at Tyrolean are in English and so are all flight deck procedures. German is used as a Classroom language for recurrent training, though.
If you don't learn at least some German you'll be able to work but will stay a bit of an "outsider".