In 1972, Dr. Francine Patterson started to teach sign language to Koko.
Koko knows and uses more than 500 words in sign language, the language of deaf people.
Dr. Patterson: Not at all! Koko has taught us that gorillas are intelligent enough to learn sign language.
Dr. Patterson communicated with a gorilla using sign language.
We talked in sign language.
Deaf people can talk in sign language.
Deaf people can converse in sign language.