The Spanish course is one of the best courses on Duolingo. I took a slightly less-developed course -- the Portuguese course and completed it. At the end of the course, I was able to have basic conversations in Portuguese. I had one half hour conversation where I talked only in Portuguese to an Uber driver and we talked about what he was doing, what he did in his spare time, etc. It was a little rough going at times b…
When we got back I continued with Duolingo but also got an online teacher and did a pile of other stuff and by the time we went south I was somewhat conversational. You can't truly learn a language with Duolingo (you especially need practice speaking with someone) but it gave me a great start.