I'd been using Duolingo for learning German for 1-2 months. Was it the right tool for learning new language? Not for me!
Duolingo doesn't take advantage of spaced repetition. I got sick and tired of successfully answering the same word for 15 lessons and then not seeing that word ever again. In total I did 2.5 units, so there was plenty of space for spaced repetition.
Overly gamified. When I do my first lessons of a day, there are so many "achievements" that they distract my focus and learning. Maybe the development could be focused better on the quality of learning instead of throwing tons of fake achievements?
I'm not a native English speaker. So I often ended up writing the longest sentence in English translation and have it marked as "false" just because of forgotten "the". Good job, Duo! You spot me...
The UI is also too primitive. For example, when I need to make a sentence out of multiple separate words provided in flashcards, I can't change the order of the words. I can only add the word to the end of the sentence, but not insert it. This again often results in having to rewrite the whole sentence, when the missing word is in the beginning of the sentence.
The overall feeling of the learning felt slow and boring. In the first weeks I was excited, because I was learning the new language. However, later when I was opening Duolingo, I felt more and more like it was a boring bureaucratic process that I have to go through. Why? Too many lessons of the same topic, too much repetition, too slow. I felt that throwing away 2/3 of the content would result in a 3 times better app.
So while this may be a tool for learning a new language, I consider it a really non efficient, non structured way of learning, having poor UX. I dumped Duolingo ~1 month ago changing my learning strategy. Now I feel more satisfied with my new learning process and feel that I'm improving faster.
What's Your experience learning languages? Have You used Duolingo?
If you speak more than one language, which you obviously do since English is not your first language, I would suggest using something else than Duolingo. Ready made courses are often not that good, and with some skill and tips, one can often cobble together a comprehensive and better programme to learn a language by oneself using all the resources that are available on the internet.
If you like SRS, Anki is a wonderful tool, and you can customise it to your hearts content. Youtube is full of people teaching German - I would suggest listening to channels that do comprehensible input. Comprehensible input is a good way to keep up morale and to get used to thinking in the language without having to constantly consult a dictionary and grammar.
A lot of people like the sentence method, where you add sentenced to Anki (along with explanations or translations), and quiz yourself on your understanding of these sentences. This is nice because you learn words, expressions and grammar in context rather than isolation.
Duolingo is a good app for people who've never learned another language before, and want a gamified introduction that holds their hand all the way. Using it doesn't hurt, but, you will move on much quicker using other methods. That said, it can be one of many tools that you use!