First of all I’d like to say the localization fallback implemented by @riking is great.
But, as it is now, it’s really hard to debug localization problems, since the fallback isn’t used in development mode. So, Discourse behaves completely different in some situations while in development mode. Is this really necessary or can we always use the fallback?
For example, I was looking into the bug “Search help doesn’t work for some locales” and had to enable the fallback by manually editing the following lines.