I guess for the majority of non-native German speakers it's easier to ask in English. However I see some people – whose mother tongue is German presumably – asking in English.
- Is asking in English actually encouraged?
As for me, the criterion I use is: I try to ask in English only if it is very difficult to write the idea in German or if the question is intrinsically German (no translation involved). I guess every body has the freedom of language choice here. But is there a useful criterion to decide?
Side note: This is the only site in (Languages).SE where the tags are in English.