In article , re says...


IFR is always English. VFR is either English or German. ATC, Flight
Information Service, and towers of controlled airports are able to
communicate in both languages. You'll hear both languages on the
frequency, depending on what each pilot prefers. The controllers switch
languages all the time.

At smaller airfields, German is the dominant language, but there is no
reason you can't communicate in English there. There is no guarantee
that the ground person manning the radio or other pilots will understand
you, even though chances are fairly good they will. At small
uncontrolled airfields, radio contact (in any language) is not mandatory
(just good practice), so that's not a show stopper.

AFAICT the situation in other European countries is similar.



Not entirely.
In France, IFR is English or French. VFR as well, at controlled
airfields. At most uncontrolled airfields, as well as
aircraft-to-aircraft communication outside of control operating hours,
French is required.