I keep getting messages saying "you are now 61% fluent in German" (same with French), then a day or so later, although I have done plenty of lessons, it slips back to 60%. It never seems to get past 61%. Does anyone know why?
Duolingo's fluency % is a nonsense number.
It says nothing about your fluency in the real world.
Duolingo's Fluency % is unreliable.
Recently appeared that the Duolingo staff had manipulated this "fluency %" for testing purposes
Duolingo will only bring you to an A2/B1 skill level in reading/writing and A1 (maybe A2) in listening/talking.
Info about language levels: https://en.wikipedia.org/wiki/Common_European_Framework_of_Reference_for_Languages
Read from "Common reference levels".
In the comments of this discussion you can read some tips to improve your German:
However, I think Duolingo's courses are excellent.
Just enjoy the courses and don't worry about Duolingo's fluency %.
My German fluency used to bounce between 65% and 66%. The highest it has been is 67%. Each day I regild any lessons that need it, followed by a couple of strength building exercises. It now seems to have stabilized at 66% and has not changed for a week. I believe that 61% is considered high for the German course. Gut gemacht!