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.