@oblomov I think @tusooa was working on such feature for #Pleroma (see merge request); not sure how that works or how far it got and if it’s working on her instance nowadays. (I hope she won’t mind the mention, either.) 
Unfortunately, Pleroma doesn’t even support language tagging yet, so there’s a long way to go. But at least it supports Unicode in custom emoji names, unlike #Mastodon and some others! 
I think #Fediverse as a whole has a long way to go toward proper language support. Not just on a technical level, but mentally, too. People first need to recognise that different languages exist and deserve equal support, that people often speak more than just one, that ASCII really isn’t enough for many of them, and so on… these first need be regarded as basic requirements, not as extra fancy features. 
