core/Lang.php

Related to this topic but off it..

@Narf what do you thing for adding support of different resource types for translations?
I can work over pull request which will add the option to pick between the current .php arrays, .po, .mo files perhaps even json's and any other formats.
It will require different loaders and parsers for each format, not too much work .
It can come inside CI 3.1 or other next version .

And perhaps a db support can be introduced too , although I don't like this option at all..

No. It may not seem as too much work to you, but it is pointless work.