What is So special about Human Language

What gives us this conceit?
How do we know that other species do not have their own lan- guages?
Perhaps we just do not understand the languages of other species. Cer- tainly, all social species communicate with one another and, ultimately, whether we call their communication systems languages is a definitional matter. How- ever, human language is different from these other systems, and it is worth identifying some of the features (Hockett, 1960) that are considered critical to human language.
Semanticity and arbitrariness of units. Consider, for instance, the com- munication system of dogs. They have a nonverbal system that is very effec- tive in communication. The reason that dogs are such successful pets is thought to be that their nonverbal communication system is so much like that of hu- mans. Besides being nonverbal, canine communication has more fundamental limitations. Unlike human language, in which the relation between signs and meaning is arbitrary (there is no reason why “good dog” and “bad dog” should mean what they do), dogs’ signs are directly related to meaning—a snarl for aggression (which often reveals the dog’s sharp incisors), exposing the neck (a vulnerable part of the dog’s body) for submission, and so on. However, although canines have a nonarbitrary communication system, it is not the case that all species do. For instance, the vocalizations of some species of monkeys have this property of arbitrary meaning (Marler, 1967). One species, the vervet monkey, has different warning calls for different types of predators—a “chutter” for snakes, a “chirp” for leopards, and a “kraup” for eagles.
Displacement in time and space. A critical feature of the monkey warning system is that the monkeys use it only in the presence of a danger. They do not use it to “discuss” the day’s events at a later time. An enormously important feature of human language (exemplified by this book) is that it can be used to communicate over time and distance. Interestingly, the “language” of honey- bees satisfies the properties of both arbitrariness and displacement (von Frisch, 1967). When a honeybee returns to a nest after finding a food source, it will engage in a dance to communicate the location of the food source. The “dance” consists of a straight run followed by a turn to the right to circle back to the starting point, another straight run, followed by a turn and circle to the left, and so on, in an alternating pattern. The length of the run indicates the distance of the food and the direction of the run relative to vertical indicates the direction relative to the sun.
Discreteness and productivity. Human language contains discrete units, which would serve to disqualify the bee language system, although the monkey warning system meets this criterion. Requiring a language to have discrete units is not just an arbitrary regulation to disqualify the dance of the bees. This dis- creteness enables the elements of the language to be combined into an almost infinite number of phrase structures and for these phrase structures to be trans- formed, as already described.
It is a striking fact that all people in the world, even those in isolated com- munities, speak a language. No other species spontaneously use a communica- tion system anything like human language. Interestingly, great apes, genetically closest to humans, appear to lack any kind of speech signal like the vervet mon- key (Mithen, 2005). However, many people have wondered whether apes such as chimpanzees could be taught a language. Early in the 20th century, there were attempts to teach chimpanzees to speak that failed miserably (C. Hayes, 1951; Kellogg & Kellogg, 1933). It is now clear that the human vocal apparatus has un- dergone special evolutionary adaptations to enable speech, and it was a hopeless goal to try to teach chimps to speak. However, apes have considerable manual dexterity and, more recently, there have been some well-publicized attempts to teach chimpanzees and other apes manual languages.
Some of the studies have used American Sign Language (e.g., R. A. Gardner & Gardner, 1969), which is a full-fledged language and makes the point that language need not be spoken. These attempts were only modest successes (e.g., Terrace, Pettito, Sanders, & Bever, 1979). Although the chimpanzees could acquire vocabularies of more than a hundred signs, they never used them with the productivity typical of humans in using their own language. Some of the more impressive attempts have actually used artificial languages consisting of “words” called lexigrams, made from plastic shapes, that can be attached to a magnetic board (e.g., Premack & Premack, 1983).
Perhaps the most impressive example comes from a bonobo great ape called Kanzi (Savage-Rumbaugh et al., 1993; see Figure 12.4). Bonobos are considered even closer genetically to humans than chimpanzees are, but they are rare. Kanzi’s mother was a subject of one of these efforts, and Kanzi sim- ply came along with his mother and observed her training sessions. However, he spontaneously started to use the lexigrams, and the experimenters began working with their newfound subject. His spontaneous constructions were quite impressive, and it was discovered that he had also acquired a consider- able ability to understand spoken language. When he was 5.5 years of age, his comprehension of spoken English was determined to be equivalent to that of a 2-year-old human.
As in other things, it seems unwise to conclude that human linguistic abili- ties are totally discontinuous from the abilities of genetically close primates. However, the human propensity for language is remarkable in the animal world. Steven Pinker (1994) coined the phrase “language instinct” to describe the pro- pensity for every human to acquire language. In his view, it is something wired into the human brain through evolution. Just as songbirds are born with the propensity to learn the song of their species, so we are born with the propen- sity to learn the language of our society. Just as humans might try to imitate the song of birds and partly succeed, other species, like the bonobo, may partly succeed at mastering the language of humans. However, birdsong is special to songbirds and language is special to humans.
■ Only humans show the propensity or the ability to acquire a com- plex communication system that combines symbols in a multitude of ways like natural language.