Since you changed things, and my 1700 words were reduced to 1500+, what does one have to do to get this number to grow?
It looks like you've learned all the words that you can learn on Duolingo :) Congrats! When we updated the lessons we took out some words that we found were not as important as other and added new words that are. The way to learn more words would be if we add more lessons and words. We're always working on adding more to the tree, so that is a possibility :)