Thank you so much for the valuable feedbacks, and I'm sorry for the QWERTY thing. We haven't thought about this problem properly and forgot there're people with different keyboard layout :)
This is an easy fix though, instead of love.keyboard.isDown use love.keyboard.isScancodeDown, and instead of using the first argument of love.keypressed/keyreleased use the second argument (the first is key, the second is scancode)
Docs for you: