The menus of the Arduino IDE are full of gibberish on this system. This only affects the menus at the top and all context menus.
When I manage to weasel my way through and open, for example, the preferences window, everything displays correctly in English. The app language is also set to English.
It appears as if the characters have gone through a sort of cipher.
A has become
B has become
A and so on.
I'm running Windows 10 64bit and the Arduino IDE version 1.8.1.