No, and that is important: Russian и corresponds to Ukrainian і, й or та, according to euphony (how well it will sound), whereas а is the same in both languages.
Go to settings. Find like keyboard, language , keyboard language, language settings , keyboard settings, something like that. Just explore and try all the stuff there is (thats what i did and i got it) because its usually a bit different for all devices. If you still cant find it, you can also just look it up on google, safari, youtube or something. Or you could try asking alexa or google home or siri or google assistant(lol i feel like i just named all technology ever made lol) and if you STILL cant find it, 1: ....wow..... and 2:maybe call or write to either duolingo or your phone company, cuz' THATs messed up. Anyway, have a great day and hope you figure it out soon! ( that probably tookme like 10 minutes to write lol) bye! :)
Check out the Alphabet songs to learn the alphabet and then check out the keyboard layout to learn where the keys will be on your keyboard if you download a new keyboard layout which will allow you to type those letters even with the keyboard you have. You will be able to switch from one language keyboard layout to the other.