Jennifer was a very bright little girl. But her accomplishment at the age of 2, though perhaps somewhat precocious, was not unique; all children born with normally functioning brains and hearing arrive at the ability to manipulate the stuff of language by, or not very much past, the age Jennifer was when this incident occurred. No member of Rex's species, on the other hand, no matter how long or how closely associated with humans, has ever learned by exposure, nor ever been taught, to do what Jennifer did so spontaneously, so early—and so effortlessly.
We readily fall into the habit of thought that if something comes easily to us it must be easy. In a real sense, it was easy for Jennifer to engage in the behavior I have described. Why? Because Jennifer, like you who are reading this now, was born equipped to learn language simply from having it used around her, as Rex was born equipped to react to moving objects by chasing them.
But when you examine human language—any language: yours, your great-great-grandmother's, your Japanese or Greek or Hungarian pen pal's—you find it characterized by a great deal of complexity. Think of the difficulties we encounter in attempting, after childhood, to learn a foreign language. No matter how many rules we absorb, we may never be satisfied with our achievement, because we still have to stop, at least sometimes, to think about whether or not we are following those rules. Even when we succeed in putting the words together into flawless sentences, someone may ask us where we are from, indicating by the question that something is still not quite right in the way we speak the language. These are difficulties we did not encounter the first time around, when we learned to speak our native language or languages.
The data – the information on which all of our questions about language rest and with which linguists grapple – are anywhere and everywhere people are found, in all the statements they make, the questions they ask, the many ways in which they express themselves in language. What do these data indicate about the nature of the activity itself – the very structure of language? Of what does its complexity consist? "Doing" language, acquiring and using it, must be possible because some commensurately complex mechanism in our brain exists to support this activity. What sort of mechanism can this be? We are not born with a particular language already in there and prepared to go to work for us. What exactly is it that we are born with? How does it work to allow us to catch on to the meanings and organization inherent in the language or languages we are exposed to from birth? Where has this ability gone when we need it, later on, to learn a foreign language? What is the relation of our language capacity to thinking, as we humans experience it?
These are some of the questions linguists pose, and the information they gather and the understanding they achieve in the course of their research into individual languages have implications for these basic questions. As we have already noted, they are not alone in the quest. Their concerns overlap with those of the other fields comprising cognitive science. Linguistics figures importantly in the quest because language, as a behavior unique to humans, can teach us much about the human brain.
The Uniqueness of Human Language
Anyone who stops to consider the phenomenon of language is aware that humans are the only species to engage in this behavior that we take so for granted. (For this reason, when I use the term "language," I will be referring only to human language, the spontaneously developing system that human children absorb from their environment and produce early and without specific instruction.) Yes, members of other species communicate with each other (and often with us) by means of bodily displays. Think of a cat arching its back and appearing larger than it normally does by virtue of its fur standing on end, or a peacock fanning out its tail to reveal a magnificent color display. They communicate by gestures, as the grimacing and chest pounding of the gorilla, for example, or the complex "dance" of honeybees. They communicate as well by vocalizations, as in the songs of birds and of whales, and the barking, growling, and whining of dogs. Students of these various types of communication have been able to describe and classify many of them and have observed their consistent pairing with certain behaviors so that we can be quite sure of their purpose. It is of course always possible that we, probing with our human faculties, are missing something in these communicative manifestations—that we simply do not understand complexities that it takes a bird's mind, or a gorilla's, to appreciate. But science requires evidence before hypotheses are considered confirmed, and we have no hard evidence to support the notion that any other species is capable of just the sort of complex system of communication that enabled Jennifer to produce her "one lip" invention.
You may be wondering at this point what the real difference is between what these other species are doing and what Jennifer did in talking about the flowers—what we humans do all the time, whether the communication is carried out in English or in Swahili or in Urdu. After all, the various systems of communication employed by other species serve them perfectly well. The cat with the arched back manages to scare off an intrusive neighbor cat, and the bird singing so sweetly generally succeeds in attracting a mate. What we have observed about the communication of other species – often called their "language" – is that each manifestation, whether of bodily display, of gesture, or of vocalization, pairs with a specific and consistent meaning. That is, a particular tail swish of your kitten or a particular utterance of a vervet monkey or a particular cry of the crow in the tree outside your window will occur under the same circumstance every time. The kitten will not swish its tail just that way to indicate anything but readiness to pounce. The vervet monkey will produce just that sound to alert other vervet monkeys that there is a snake in the grass. The crow will caw in just that fashion always and only to warn intruders to keep out of its territory. The display or gesture or sound will be inseparable from the given situation.
You, on the other hand, can separate your vocalization from a given situation. For instance, you can communicate something about the future: You can tell the friend who calls to invite you to lunch that you can't go because you have to finish this book on cognitive science, when what you really have in mind is a nice nap. Not only are you expressing something about the future, but what you are saying isn't even true. Your language affords you as much freedom in what you express by means of it as your conscience allows. The bee that communicates the location of food to its hivemates does not produce movements that will lead them to fly south for a certain distance and then when they get there produce movements that communicate "ha, ha, just kidding." There is something quite different in the process we are engaging in when we use our language from what bees are doing when using theirs. One of the unique and telling aspects of this difference is the fact that we are able to separate what we express from the requirements of the moment, to convey concepts ranging from the factual and true ("I'm on my way to work/class") to speculations about what would happen if the situation were different ("What if I were to hang out in the mall instead?") to out-and-out lies ("I'm really sorry I didn't come in yesterday, but I wasn't feeling well"). This ability makes possible our use of language for the large and varied set of intellectual, aesthetic, emotional, and social purposes characteristic of human behavior, ranging from the straightforward transfer of information to the exploration of ideas, from poetry to deception, from sarcasm to joking and play.
Characteristics of Human Language
Although the differences among languages spoken in different parts of the world fairly jump out at us, these languages are in fact far more similar than we generally perceive. That this is so is not surprising, for all human languages—those known only through historical documents and comparative studies as well as those currently spoken—reflect the linguistic capacity of the human brain.