Hi! If by breaking you mean that letters like á or ö or different alphabets don't appear then I recommend searching for fonts that support your language and switching it out with the one included.
If you mean that certain elements can't be translated in Ren'py... Yeah, because they're images (found in the gui folder) so you need to edit those in any image editor.
It was the very first template I made and I didn't really account for worldwide use tbh.