Many (1. RESEARCH) ____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 line using (2. LANGUAGE) ___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. Loko, a 400-pound lowland gorilla, is claimed to have understood a poem (3. WRITE) ____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 (4. SCIENCE) ___scientists _____at the forefront of this research admit that their work has been severely criticized. The skeptics in general claim that apes’ language (5. BEHAVE) ___behavior_____is merely imitative. For this behavior to be called “language”, it must also be (6. COMMUNICATE) ____communicative____. The proponents of ape language counter that those who deny the (7. VALID) ___validity _____of this research have never worked with apes. They point out that new fields of investigation always create (8. CONTROVERSIAL) ___controversy_____. They add that (9. HUMAN) ___subhuman _____primates have not been taught to speak, however, because the outer layer of their brain hemispheres is not (10. SUFFICIENT) ___sufficiently _____refined.