I plan to be involved with Flarum in the long term for both personal and non-personal projects, so I will actively update the Spanish package, however I also want to help in this if that is the way to go.
I really agree with @luceos that having a single organization would be useful, I mean if I now go to my composer and want to install X language it's not easy, in fact I always have to look at the package names, instead with this it would be as easy as putting flarum-lang/
and the language name and check at that moment if that language exists or install it.
I think at some point the languages had to be official in some way, precisely for maintenance and clarity (the user has to know what to install), there are communities that are completely in another language so its maintenance is as important as the core extensions.