Are questions about User Interface messages or menu items involving languages other than English on-topic ?
Also, are questions about problems with translating/converting a UI from English to other languages on-topic ?
2 Answers
Yes, all of the above is on topic.
Yes, but since the audience is primarily English (and generally expected to be able to use English) the question itself should be in English, and it's most helpful that any non-English text in screenshots/etc is translated/explained unless it doesn't get in the way of answering questions.
As for translating an interface, that's what the language, localization and internationalization tags are for where appropriate!
