Francine Patterson was a very smart lady who taught a very special gorilla named Koko how to communicate with people using sign language.
You know how mommy and daddy talk to you using their mouths and words? Well, Koko learned how to talk to Francine using her hands and signs!
Koko and Francine became very good friends and Koko was able to express her feelings and tell Francine what she wanted. Just like you can use words to ask for things or tell people how you feel.
Koko was very good at sign language and even learned over 1,000 different signs! That's like you learning how to read and write lots and lots of new words!
Thanks to Francine's hard work and love for Koko, they were able to communicate and understand each other in a very special way.