See the tree?
Where can I see how I'm doing on my Spanish tree? Or is my tree my "Home" page. (See personally I thought the tree was a tree and it showed like how many branches or stems you've completed.) Does that sound weird? If this doesn't make sense I can try to explain more. I often know what I want to say, but I don't know what words to get out. For any help anyone gives, " Gracias, mi amigos!" ("thank you my friends!")
Once you've completed all the skills in your skill tree, you can keep learning by strengthening weaker skills and by using other resources to become more proficient.
Here's an article from the Duolingo Wiki regarding language "trees":
If you scroll down you can see the end of the tree. There won't come more skills.