Chimpanzees have an undescended larynx, and they find it very difficult to produce the speech sounds of human languages. A number of different methods have been devised over the years to get around this problem, most notably, the use of ASL (American Sign Language) and Lexigrams.
Examples of chimpanzee language studies that used ASL include the Gardners’ and later Fout’s work with Washoe and Herbert Terrace’s project with Nim Chimpsky. There are even gorillas that use ASL: see the link below to Francine Patterson’s site for Koko.
The advantages of ASL are:
(1) It’s an existing language used by the deaf community;
(2) A chimpanzee can be encouraged to produce a sign by a method called moulding that allows a human to shape the chimp’s hands into an approximation of the sign;
(3) No special technology is necessary for ASL.
The disadvantages of using ASL for chimpanzee communication are as follows:
(1) ASL is a language spoken by deaf individuals; One can’t become truly fluent in ASL without a process of immersion. ASL is not a form of English or any other spoken language. Most chimpanzee language researchers are not fluent speakers of ASL. Because of this, they are not competent to teach ASL to anybody, least of all a non-human.
(2) The gestures of ASL are difficult for a chimpanzee to learn because the chimpanzee hand and the human hand are not designed for exactly the same motions. True ASL speakers who have observed chimpanzee signing have complained that it isn’t accurate.
(3) Chimpanzees sign faster than most humans can see. If you are not fluent in ASL — and even if you are — you are going to miss a lot of what the chimp says.
An alternative method, pioneered by Duane Rumbaugh with Lana, and perfected by Sue Savage-Rumbaugh with the bonobos Kanzi and Panbanisha and their families, is to use lexigrams — abstract printed symbols to stand for words. Most lexigrams bear no relationship to either the meaning or the pronunciation of the words for which they stand. However, lexigrams stand not for ideas, but for words in a particular language. So, for instance, when Kanzi presses one of the lexigrams in his keyboard, he is selecting a particular English word for which it stands. Kanzi and Panbanisha are fluent in English, and their use of lexigrams permits them to communicate in English.
The advantages of a lexigrammatic system such as Sue Savage-Rumbaugh uses with her bonobos are:
(1) The spoken language that the researchers use can be represented by lexigrams; thus fluency for comprehension that the bonobos may have acquired by daily interactions with caregivers can be translated into fluency in production, using a lexigram keyboard. Neither researchers nor apes have to acquire a whole new language in order to communicate with each other.
(2) There is no special dexterity required. Lexigrams can be selected by pointing at a printed sheet or by pressing a key on the keyboard.
The disadvantage of lexigrams, as used by other researchers, are:
(1) The apes are limited to the symbols on the keyboard. If they want to use a word they know, but have no lexigram for, they are stuck.
(2) If used with an inflectional language, such as English, lexigrams limit the ability to speak grammatically. For instance, if you have a lexigram for sing, you can’ t use sangor sung, so you end speaking ungrammatically.
(3) Nobody but the researchers and the apes know the special symbols on the lexigram keyboard. This limits the ability to communicate with strangers, or to surf on the internet.
When I adopted the lexigram system for Project Bow I wanted the best of both worlds. I wanted a standard system of communication. I wanted to be able to speak with Bow in languages I am fluent in. And I wanted him to eventually have unlimited access to any word he wanted, in any grammatical form. This is why I chose to make our lexigrams in the standard orthography of each language.
What does this mean? It means that lexigrams that stand for English words look like English words. Lexigrams that stand for Hebrew words look like Hebrew words. Bow wasn’t required to think of the lexigrams as being composed of letters. He could just memorize each of them as a whole symbol. But the information was there. It left him free to communicate immediately with new friends as well as people he had known all his life. And it paved the way for true literacy.
The design of Bow’s lexigrams is one of my major contributions to the field of ape language research.
Examples of Bow’s Lexigrams in English and Hebrew
