This is probably not going to be in the demo for quite some time unfortunately, I'm not even sure it will be possible at all.
I have recently added support for a more standard font in my internal version but right now I can't say for certain what form of code table it supports, I'll have to look into that further later.
And yes, currently you have to replace the "en" localization file to be able to translate the game.
It's not really ready for localization yet so therefore only English exists in game right now.