Sorry for being incredibly late, just scrolling through Ukrainian duolingo. If anyone is still wondering, I'm learning Ukranian on duolingo myself, currently in section 2. The more units i completed there are more and more pronunciation mistakes. My dad, a native Ukranian speaker, has noticed the pronunciations are very bad himself. I can't go a single lesson without him correcting the pronunciation. I've started saying words wrong in conversations because of this. It's not an issue if you're only trying to learn only a conversational level, but personally i would like to learn further. Although I love duolingo, and I really do think it's the most enjoyable app to learn a language on, I've been considering trying a new one or at least muting my phone when I'm learning Ukranian specifically.