I had Spanish in high school and am using this app as a refresher, as well as to some more. The greatest annoyance, by far, is how fast skills go down. Its unrealistic that I need to suddenly review 5 skills after around 12 hours of inactivity, when I just reviewed them back to gold the last time I was on. Then there are times when I wont have Internet access for around 3 days, and Ill have to do a months worth of reviewing. Id end up repeating and reviewing the same three to five skills for weeks, and they still wouldnt stay gold for at least two days. Thus, my progress through the course is slowed significantly, lest I decide to ignore all the skills dropping from gold. At that rate, Id imagine youd want me to review "Basics 1" when Im done learning the last available skill? Maybe if I ignore all my skills going down from gold, I can try the chats with bots?
Id put 5 or 4 stars, but the unrealistic frequency of reviewing is a major downside to using this app. The health system is fine and understandable. Just please: improve the review frequency.
That aside, if you really dont mind constantly reviewing (or seeing skills fade away from gold), Duolingo is a fantastic app to use to learn/relearn a language. Currently, Im using the app to master Spanish and learn Japanese.
Btw, for Japanese, please add the feature that allows us to hear the speaker slowly, if youre not going to put furigana. And I look forward to the day the Japanese course gets listening, speaking, and actual writing (typing) exercises.