I know it can be done. My phone has a Spanish option, but it’s a lot harder on the PC.
I agree. I prefer using the Android phone for Duolingo. It would be painful on a PC. When writing in ONE language on the PC, switching the language on the PC and getting the right keyboard helps. I still make mistakes typing on a native German keyboard.
For "fun", I changed my Facebook application language to Welsh. The app is nicely internationalized. I wouldn't dare try that with Japanese.