KOREAN LANGUAGE SPELLING
Why there is no lessons in Korean that teach you how to spell with microphone
I'm also not sure I understand what you mean. Si tu préfères, tu peux reformuler ta question en français :)
If you're issue is with the alphabet (as implied by the use of the word "spell"), I can suggest you some other resources to complement Duolingo at this stage of your study. But your level 8 flag tells me you're probably already beyond this point.
Or do you mean you'd like to have exercises that require you to speak and have the computer recognize your voice?
They may get it sometime in the future. I can't really give an answer as to when, or why they don't have these exercises. Good news is they now have the typing exercises.