TLDR: if browsing a map for French wiki, and a city only has a Russian and
Chinese name, which one should be shown? Should the city name have
different rules from a store or a street name? ...

I have been hacking to add unlimited multilingual support to Wikipedia
maps, and have language fallback question:  given a list of arbitrary
languages for each map feature, what is the best choice for a given
language?

I know Mediawiki has language fallbacks, but they are very simple (e.g. for
"ru", if "ru" is not there, try "en").

Some things to consider:
* Unlike Wikipedia, where readers go for "meaning", in maps we mostly need
"readability".
* Alphabets: Latin alphabet is probably the most universally understood,
followed by...? Per target language?
* Politics: places like Crimea tend to have both Russian and Ukrainian
names defined, but if drawing map in Ukrainian, and some feature has
Russian and English names, but not Ukrainian, should it be shown with the
Russian or Ukrainian name?
* When viewing a map of China in English, should Chinese (local) name be
shown together with the English name? Should it be shown for all types of
features (city name, street name, name of the church, ...?)

Thanks!