It would be great to have a particular highlight mode (in addition to bold and italic) for languages other than the main language of the post. Currently, it appears that italics are the way to go on this site, but I find that limits legibility. That's mostly because italics are an emphatic mode used in normal text, but also because the font used in StackExchange differentiates little between the two.
At the very least, there should be guidelines about how to write what language, how. Or maybe I missed the guidelines and they already exist? Ĉu iu ajn opinias ion?