The Speaking Creature

35 it speaks You are walking, let’s say, with a companion—a very human thing to do. Walking in a truly upright fashion, that is, as only humans and our close ancestors have been walking for more than three million years, across savanna and desert, meadow and snowfield: feet landing heeltoe , heel-toe, in a natural gait of perhaps two and a half miles per hour, each knee slightly bent and then briefly locking as the leg extends, trunk and torso balanced above the hips and swiveling just a little with each stride, shoulders slightly forward of hips, arms and hands moving in easy rhythm, fingers loose, head up and eyes alert to sights and movements within an arc of vision almost 180 degrees wide—wider, if the head turns even slightly, as it does now when you speak. You say, “So, what have you been up to?” Now before we even consider the answer, consider all that goes into the question. To begin with, you have to have a neocortex—that part of the brain that formulates thought—large enough to handle the task. If nonfiction THE SPEAKING CREATURE PHILIP GERARD 36 Ecotone: reimagining place you were inside an MRI (Magnetic Resonance Imaging) chamber as you spoke, your neocortex—the “new bark,” or most recently developed portion of the brain—would light up like a pinball machine, signaling that thoughts were being formed. Or perhaps the electrical activity itself is the thought. Very smart people are wrestling with this question. We’ve had our extremely large neocortex for only about 250,000 years, so it’s still something of a novelty. Only mammals have one. Only we humans have such a big one. It typically occupies about 75 percent of the brain’s volume, about a hundred meters of “wiring,” a hundred billion cells, folded into six layers of neurons: nineteen billion in the average adult female, twenty-three billion in the adult male. In other words, a lot. All of our higher functions are controlled by the neocortex: selfawareness , sensory perception, conscious thought, and language. It is, literally, our gray matter. Once a thought is formed, the neocortex then has to encode it into a string of neural impulses that pass into nerves leading into the face and torso, activating the fine facial muscles that control the jaw and mouth and lips and tongue, as well as the muscles regulating the larynx and diaphragm and lungs. Air must be forced out of the lungs by the diaphragm (a sheet of muscle under the ribs) and up through the larynx (a box of cartilage and muscle in the throat) and past the vocal cords (two membranes excited by the pressure of air as it travels past them) which must vibrate in a particular sequence and pitch. In the mouth, the tongue and an assortment of mouth muscles with complicated Latin names manipulate the airflow and vibrations to create an ordered sequence of sounds—fricatives, plosives, nasals, labials, dentals, and velars (hang in there)—while, inside the ears, the auricles, the tympanic membranes, the spiral cochlea, and the organ of Corti act as a kind of stage monitor to let you know instantly whether you are making the correct sounds and at what timbre, pitch, and volume , so you can adjust your speech accordingly. All of this apparatus is remarkably specialized, perfected by function , shape, and size beyond what any team of super-engineers could accomplish in a thousand lifetimes, to form just fifty sounds. If that doesn’t sound like a lot, consider that apes can express only a dozen. And that’s just the basic hardware. There’s also the software. The brain has already given a whole set of subsidiary instructions about the utterance which is still in the process 37 philip gerard of being uttered: how loud—at a conversational volume, or a bit more forcefully in order to reach above traffic noise, or perhaps in an intimate whisper? And what will the tone be—friendly, distracted, passionately interested, sarcastic? How will the words be inflected—at what speed will they come out, in what sequence, with what emphasis? And oh yeah . . . in what language...