isMultilingual() loads all languages just to check if there is more than one

@berdir, do you still think your solution in #8 will not work?

Why should not we store the result of isMultilingual() like this?

Ha, 7 years later, forgot about this issue *again* and recently created a new one, with a new approach: 📌 Add caching to ConfigurableLanguageManager::getLanguages() Active .

I think this is still interesting, it does require a container rebuild every time a language is added. I'm unsure what's better.

Closing this as a duplicate of 📌 Add caching to ConfigurableLanguageManager::getLanguages() Active , that gets rid of the query, a container parameter based on config entities would definitely be more complicated.