Is there a limit to how many languages you learn? Is there a max for each level?
I can remember Italian, French, and Spanish well. Esperanto is pretty meh. Dutch and German are rusty but I'm gonna practice them soon. As for the other languages, I still have a lot of vocabulary to learn before I can really "speak" them even though I'm pretty familiar with how a lot of them work in terms of grammar.
I've been on here for almost 2 years now, so I think that's how.
There are no limits to how many languages you can learn. It's best if you learn one language at a time, two at most. Unless you're not sure which language to learn, in that case it's better to try all the lessons Duo offers then see for yourself which one(s) you like.
The maximum level is 25, but that is determined by XPs and not your knowledge or fluency.