Many researchers believe that apes

Many researchers believe that apes can communicate with human beings. Investigations made at several laboratories in the United States and elsewhere indicate that chimpanzees and gorillas are capable of understanding language and using linguistic responses at the level of a four-year-old child. Washoe, an adult chimpanzee who was raised as if she were a deaf child, can translate words she hears into American Sign Language. Koko, a 400-pound lowland gorilla, is claimed to have understood a poem written about her. Tests of Koko's auditory comprehension show that she is able to make discriminations between such words as "funny," "money," and "bunny." The scientists at the forefront of this research admit that their work has been severely criticized. The skeptics in general claim that apes' language behavior is merely imitative. For this behavior to be called "language," it must also be communicative. The proponents of ape language counter that those who deny the validity of this research have never worked with apes. They point out that new fields of investigation always create controversy. They add that subhuman primates have not been taught to speak, however, because the outer layer of their brain hemispheres is not sufficiently refined.