This question is perhaps related to a previous one here entitled Handling questions from non-english writers and I have seen similar discussion entitled Is English required on Stack Overflow?.
My now researched understanding is that Languages Other Than English (LOTE) are not allowed in Stack Exchange Questions except in language specific sites such as French Language & Usage.
However, LOTE seems to occasionally creep into questions (like How to fix "import qgis.core ImportError: DLL load failed") in a similar manner to what we see with signatures, taglines, or greetings.
With respect to signatures, taglines, or greetings our help is clear in what to do:
Do not use signature, taglines, or greetings.
Every post you make is already “signed” with your standard user card, which links directly back to your user page. If you use an additional signature or tagline, it will be removed to reduce noise in the questions and answers.
Your user page belongs to you — fill it with information about your interests, links to stuff you’ve worked on, or whatever else you like!
If we see LOTE used, should it similarly "be removed to reduce noise in the questions and answers"?
I am a confessed francophile with high school French so don't think me xenophobic, but I know through personal experience that it is now easy to read/write rudimentary Italian and Korean with the aid of Google Translate.