Can Gorillas Learn to Talk?

Apes cannot learn a language in the human sense. Therefore some researchers have tried to teach them sign language. The first gorilla to receive language training was Koko. She was born in San Francisco Zoo in 1971. When she was 6 months old, Francine Patterson started to care for her and to teach her sign language. After only 2 weeks, Koko used two signs: those for 'eating' and 'drinking'. After 10 years she had a good command of 500 signs and she had correctly used 1,000 signs at least once. She learnt the signs by imitation and by having her hands moved into the right position by her teacher.
Francine Patterson admits that the dialogues with Koko look completely strange to outsiders and that her answers have to be interpreted first. However, the experts differ considerably in their opinion on these interpretations. Dr. Patterson thinks that Koko's I.Q. lies between 85 and 95, i.e. at the lower level of normal human intelligence - however, other scientists don't agree with her at all.

In their natural habitat, gorillas communicate with many vocalisations.