Why don't you use .po (=>.pm) files for language variants ? Why is all hard coded in exe/dlls ? Users of unsupported language variants could easily make their own translations.
Is there a specific language that you want to see added? It would be great to create a feature request for that language if there isn't one already so that we can see how many other users would be interested in this change.
When would be used .po/.mo files for languages, then would be very easy create any language by users (or replace with own file some exist language), but whe it is compiled to program, it is always for nothing...
My language is czech.