Speaking as a total ignorant from a coding perspective. But I guess that wouldn't be the hard part, considering that most of Duolinguo is just boxes and text inputs. How difficult it is to create a database of competent linguists with an efficient training who can progressively enhance your understanding of languages?
Thanks for the insight. I can see that, maybe a vocabulary builder.
Though I’d bet your time would be better spent doing other things like Anki or consuming media in the language instead, though some people just need/want the gamification.