If there a way to set the language on a specific user or pass it on to the URL to the software to force it to load in a specific one?

I found the documentation on how to translate files and the software, but I'm quite impressed with how basic everything is. Should there not be a "locale" option on accounts? I can't potentially believe I would need to install a second version in order to have a second language fully working. That would make no sense because there is a reason why the language files are in their own folder. Unless the software strings are not fully isolated and localize on their own files which would mean that indeed you would need a second installation and clone to have it working in a different language.