To get non-English language text to display in-game, the game needs to be aware of those particular characters. Not all fonts include all characters. To change this one would need to change the font that is displayed in-game. There are some instructions on how to do that here. Beyond changing the font, the text would need to be changed as well to read appropriately since not all languages have a direct correlation between characters.
Please note, I have not tested the process described on the linked mod. Nor am I certain that simply changing the font will resolve it, but it is a good place to start.