Congrats on the initiative! Sadly, I won’t be able to participate but would love to read the outcome. Still, I would like to highlight one issue that, at least in Mexico, may be hindering progress: the lack of a consolidated community devoted to discuss this (an other) issue(s). Most efforts are individual ones and on a case-by-case basis. Of course, there are some efforts but still minor (to my view; and usually at large universities) and they certainly don’t deal with language-barrier issues (as far as I know). Perhaps reaching out to those who are leading some of these efforts can be a way forward.
I agree with @llrs in having several languages supported by the same package and with @lauracion on the specific comment about language-specific topics regarding special characters (I have always found that very frustrating). Finally, examples like the one @noamross provided, seem like a potentially simple solution (provided someone(s) would do so for as many languages as possible).
Thanks!