I reached 57% fluency last week and despite working on duo every day since, I can't seem to get to 58%.
Has anyone else found it difficult to gain percentage points?
I think there is a maximum somewhere that is much less than 100% because you can't become fluent by using Duolingo as the number of words is probably between 1250 and 1500. However, even 1500 words can be reasonably fluent, so the maximum might be about 65-70%.
If you make mistakes, I think that will lower your score but even if you don't make mistakes, the number of words you've been exposed to will depend on how many exercises you have completed.
Check your word list and for the number and their strength and that might give you more of a clue. And if you find someone higher than you, you could ask to compare. (I have 47% in Spanish with about 1250 words, although I was 51% at one point...)
So if you're currently plateaued on 57% it might be that while you're not making mistakes, you might be using the same list of words as there aren't many more, and so it's a random chance for meeting the ones you haven't encountered yet.
That's just my take on it.
You're welcome. :-) I'm quite enthusiastic to talk about this stuff as I've been asking myself the same questions and looking around for answers.
After researching it, I think if you have no other exposure to the language Duo gets you to about A2 standard on the Common European Framework of Reference for Languages.
Repetition will keep the learned vocabulary in your memory and after a certain amount of that, it will be well seated in your long term memory.
To progress a bit more, some people recommend doing the reverse course from the opposite language. That's what I've started to do with Spanish.
Otherwise, you're ready to converse with people, read news, articles or books, listen to podcasts, and watch movies with subtitles with either English progressing to those of the target language. Of course, there's also loads of other resources on the Internet.
That way you should quickly progress to B1 and onward. :-)
Lots of people also start on another language as it seems a relatively painless and enjoyable way to get to that A2 standard. I've found Esperanto is an interesting one that is quick to learn, and that's led me on to French.