chapter 3 assignment koko

While ASL is indeed a full, complete language (incidentally, unrelated to English), does Kokos signing demonstrate that she was using ASL at its full extent?  What level of fluency did Koko demonstrate?  What does this indicate, if anything, about how closely related humans are to other apes?

http://www.bbc.com/earth/story/20150820-can-this-gorilla-talk#:~:text=ORIGINAL%20STORY%3A,years%20of%20living%20with%20humans.&text=If%20you’ve%20read%20the,mastering%20the%20ability%20to%20talk.