To continue dumping on Duolingo: we had one guy join our D&D group intended to improve our target language (so all interaction at the gaming table in target language) who swore he had done two years of Duolingo and was well prepared. Couldn't speak a lick of the language so it was only English from them the whole campaign. Want to learn a language? Please don't do it with Duolingo.
I've been using Duolingo for almost 2 years now. It has learned me to understand the language a bit.
But don't ask me to build a proper sentence myself. I'm utterly lost in that case, because it doesn't teach you having a real conversation. That includes even the most simple real life things like ordering at a restaurant and then complain that your food is cold.