I started playing with Duolingo back when it was in private beta, though I didn't make it a regular habit for another year or so. I've been pretty regular since early 2014, however, and I think it's great. I've been doing French and German the longest. I'm at Level 24 in each of them, and have finished all the lessons available in French. I had been on track to finish German not much later, but suddenly the German lessons were revised to add a whole lot more material. I'm not complaining, and hope they will do so for the French at some point. For now, I'm still making my way through new German lessons while constantly reviewing the French. I chose French because that's the language I spent 3.5 years learning in school, and German because of our Swiss family. Sadly, Duolingo has no Swiss German lessons, so High German will have to do. High German is more generally useful, anyway, but I do find myself resenting having to type the eszett, which isn't used in the Swiss version of High German but is required by Duolingo.
At some point in 2015 I added Spanish (now Level 13), out of a feeling of obligation. I live in Florida, and that makes Spanish the most practical foreign language to learn. No doubt because I am learning it for duty rather than love, it is my least favorite of the languages. I'm hoping I'll like it more as I get better at it. It took me quite a while to start liking German....
This spring, when we travelled to Venice, I added Italian (now Level 9), just for fun. I'm enjoying it, especially when I note the similarities and differences with Spanish and French. I'm hoping we'll eventually manage a trip with friends to Cortona, where it will be polite to have at least a little Italian.
Am I learning anything? I'm certainly not becoming fluent. (I have yet to figure out how Duolingo does its calculations. It claims I'm 49% fluent in Spanish, a bald-faced lie if there ever was one.) And even though I practice speaking along with reading and writing, I know I couldn't carry out a decent conversation in any of the languages. Or even a halting, broken conversation.
However, that does not trouble me. What I am doing is increasing my familiarity with the languages, educating my ear and my speech, picking up some grammar and vocabulary, and preparing pathways in my brain for a time when I might have the opportunity to learn in a more interactive situation. I hope that by laying a foundation now, I will make faster progress at that hypothetical time. In any case, it's fun to understand a few things I did not before: When I saw a restaurant named Cena, I recognized the Italian word for "dinner."
It has also been interesting to note changes in my learning as I progress. At the beginning, I made sure to separate my language learning sessions. If I studied French in the morning, I'd tackle German in the evening. Otherwise, I'd get confused. Then suddenly, I didn't. And I really mean suddenly. All at once I could switch between languages with no interval in between. I don't mean that the German word won't sometimes come to me first when I'm working in French, or vice versa, but it doesn't happen often, and it no longer bothers me. The hardest, now, is between Italian and Spanish, because both are new to me and so many words are very similar but not identical.
I do Duolingo both on my laptop and using the app on my phone. The interfaces are different, and each is valuable in its own way. Right now I'm in a routine of using the phone most of the time, because I do my Duolingo lessons as part of my daily exercise (more on that later). For each language I generally do the suggested review ("strengthen") and then one additional lesson (except in French, where I've reached the end). The process is slower on the phone, but since I'm exercising at the same time, that's not a problem. Obviously I can't keep the same learning schedule when we're travelling, but as long as there's an Internet connection available, I can do enough that catching up is not difficult.
It's even more fun to share Duolingo with family members and friends!
Once we get back on our "normal" school schedule, I'll be starting my routine again (with Duolingo and other things). I've got to get back to my bullet journal.
I'll be looking forward to seeing your activity on the boards. Jonathan and Joseph have been busy elsewhere recently.