Is there any progress of so call "replacement translation" function?

Is there any progress of so call “replacement translation” function?

@nephele do you have a roadmap?

I think that the concept of “overlay language” is already here in Haiku. At least that’s what I understood from the previous comments about how to add traditional Chinese translations for Hong Kongese users. You should maybe send a gentle reminder to @nielx who is the admin for this matter, whereas @nephele I believe was simply chipping in with his advice?