Do you know crowdin.net? It's a collaborative translation tool, free for open source projects. I found it is used by other crypto communities to involve as many people as possible in the translation process in a transparent way.

Maybe it would be a good idea to create a project there for missing languages as well as those where translation quality is, delicately speaking, unknown, so that it can be improved by native speakers? Additionally, it should be much easier to add translations should you add new English content.