using keyboard with iPad

I have been using the Duolingo app to learn French for a year. Using the touch screen keyboard there is no problem. I have however recently bought a magic keyboard and find that certain keys do not show correctly on the screen. Thus when M is pressed a comma appears on the screen and in order to show an A I have to press Q. The problem only appears with certain letters and symbols, others work perfectly well. I have subsequently changed my magic keyboard for a Smart Keyboard but the same problem recurs. I have checked the language settings for the keyboard and it is only set up for English and French - qwerty in both cases. Help please as the keyboard is unusable with this app - in general use it works fine.