Thanks for your help, Naphier. When I went looking for information about the key codes I realised how problematic it might be.
Your solution looks like just the thing, I'll get to work on implementing that.
I was investigating how I can work a physical keyboard with a different language layout into it, but strangely my tablet completely ignores me when I try to switch the language settings for the physical keyboard. Which means the keycodes being sent to the game are still the English(US) ones. So that may or may not happen, but the soft keyboard will do the trick and I'm happy with that.
When I'm done I'll post what I've made in case anyone else finds it useful. There will be a German, French and Spanish version, maybe Danish also.
I bring cats for all.