Koko the Gorilla, who was adopted by the San Diego Zoo, can use over 1000 hand signals and understand over 2000 english words!
In 1998, Koko and Penny, the director of research at the zoo, spoke over AOL instant messenger and by phone to around 20,000 people. Penny would help tranlate what Koko signed and people logged in would ask questions or phone and directly ask Koko the question, and she would respond as best as she could.
The whole chat sequence was typed and people asked about how many friends Koko has (2 dogs, a cat and 2 other gorillas), how Koko refers to herself as "Fine Animal Person Gorilla" and about how she wants to start a family when she can. The purpose of this was to draw attention to the declining population of Gorillas and Primates due to urbanization and deforestation. People seem to love Koko, even though she calls humans "nipples".