Can apes be trained to use language as human beings do? Can they learn the importance of word order? Should language be defined as communicative behavior? Is the human mind unique, or part of a long continuum that includes animals in the gradual development of many complex talents related to speech?
These are the kinds of questions being asked by experimenters teaching American Sign Language to chimpanzees and gorillas. According to Ted Crail in ''Apetalk and Whalespeak,'' the linguist Noam Chomsky says that apes cannot go beyond ''. . . the barest rudiments of language,'' for (in Crail's words) ''. . . only humans have an innate capacity to learn language. . . .''
In the first paragraph of ''The Education of Koko,'' Francine (Penny) Patterson claims something quite different: ''When I began teaching Koko American Sign Language nine years ago, I had no idea how far she would progress with it. There was little reason for me to assume that a gorilla could learn to use language to rhyme, lie, joke, express her emotions, or describe her world.''
Patterson goes on to describe the history of experiments in teaching apes human or symbolic languages. The question of word order, whether the apes understand and use syntax, ''. . . remains unsettled.''
One of her critics, Herbert Terrace of the University of Pennsylvania, claims that apes cannot create true sentences. In his book ''Nim: A Chimpanzee Who Learned Sign Language'' (New York, Alfred A. Knopf, 1979), Terrace takes the reader step by agonizing step through the problems he encountered in carrying out his research. Nim had more than 60 teachers in 44 months of the study, resulting in ''emotional turmoil'' for the chimpanzee. One is left with the feeling that somehow Terrace's project failed -- at least for Nim emotionally -- because the ape suffered too often from the loss of favorite teachers.
With a refreshing tone that is free of bitterness, Penny Patterson, in ''The Education of Koko,'' tells the tale of her own difficulties: acquiring the gorilla Koko from the San Francisco Zoo, housing her at Stanford University, and finally moving her and her future mate, Michael, to a farm near Woodside, Calif. To continue her experiments in ape mentality and language acquisition, Patterson founded the Gorilla Foundation in 1976. She graduated from Stanford University in 1979 with a PhD in developmental psychology and is now the Gorilla Foundation's president and research director.
She is informative but never overbearing as she sorts facts about gorillas from fiction, briefly defines her view of the scientific process, and talks about sign language and how it differs from English. She discusses her approach to gathering data on language production and comprehension and details her procedures and methods (such as double-blind testing), designed to avoid critics' charges that signing apes are cued, that they mimic their teachers far more than they sign spontaneously and appropriately.
Patterson believes that essential information about her gorillas' language abilities can be gathered only by combining controlled routine data collection with a case-study approach. The importance of detailing incidents of language usage as they occur becomes abundantly clear when she describes Koko's imperious , stubborn temperament, and the gorilla's inclination to make deliberate mistakes when she becomes ''bored'' with repeated testing.
In an engaging style illustrated with photographs and specific examples of dialogue between Koko and Michael and their trainers, Patterson describes the gorillas' routine; their play, signing to themselves when they think they are not being watched; their rhyming and swearing; their word innovations, lies, evidence of imagination, gossip, and dreams; and their view of the world when asked for it.
In her conclusion Patterson reminds us that gorillas are not human, though in experimental situations they are judged too often by human standards. Nor are they subhuman in any way. ''Each species represents a different solution to survival,'' she says, and the differences between man and ape are ''. . . due to chemistry of many faculties more developed in man than in gorilla.'' Critics of her work ''. . . fail to see that the problem is a misunderstanding of the purpose of language.''
In a sometimes acerb but exhaustive analysis of the arguments between behaviorists and linguists (''The Ape's Reflexion,'' New York, the Dial Press, 1979), Adrian J. Desmond sounds two cautionary notes about Patterson's conclusions. First, they should be based on analysis of the gorillas' total output. Second, assumptions cannot be made about the apes' meaning of words like sorry, which has a human sociological basis.
In ''Apetalk and Whalespeak,'' Ted Crail, director of creative services at the Animal Protection Institute, also concerns himself with arguments about language and the uniqueness of man.
After considering communication techniques used by various animals, he devotes a third of his book to an anecdotal history of the ape-language experiments. Though not as rigorous as Desmond, he strongly supports Penny Patterson and is critical of Herbert Terrace. Apes are not enormously creative, he emphasizes. Why not return to the drawing board if new facts defy theory?
Reporting anecdotes of serious attempts to communicate with whales, Crail quotes extensively and explores the personalities of experimenters such as John Lilly, the pioneer in dolphin studies; Roger Payne, who has taped whale songs every year since 1957; Jim Nollman, who approaches whales with music; and Dr. Lou Herman of the University of Hawaii, who hopes to establish two-way communication with dolphins.
Most of the authors of the books discussed here seem to agree that human identity is at stake in the ape-language experiments, but in-depth consideration of the issue can also lead one to the conclusion that this line of reasoning has been overstated and is little more than a presumption.