I proposed something similar in An Alternative to Translation for Non-English Speakers?. I'm glad people are still discussing this issue.
I'll propose something lighter-weight now. Let's have the poster always first try his/her post in his/her best English. If he/she then feels he/she can do a lot better in his/her native language, then let's recommend he create/she creates a separate section in that language:
La misma pregunta, en español:
He propuesto algo similar en an alternative to traducción para no sean en inglés oradores?. Estoy contento de personas aún están discutiendo esta cuestión.
Te propongo algo ligera ahora. Vamos tener el póster siempre primero intentar su puesto en su mejor inglés. Si siente entonces él puede hacer mucho mejor en su idioma nativo, y vamos recomendar crear una sección aparte en ese idioma:
If someone speaks the other language, then they may use that version to help clean up the English version. As some will no doubt notice, my Spanish is no better than that of Bing Translator, yet even I could get enough information from a question in Spanish, Italian or French (or maybe Portuguese) to use that information to help clean up the English version.
It's still the case that all answers are to be in English. That should never change.