The Anatomy of Speech

Human speech is a remarkably complicated cooperation of our brain, mouth parts, tongue, voice box, and breathing apparatus. Most anatomists and paleoanthropologists studying human speech and its origins have focused on the brain. After all, it is the brain whose significant enlargement in humans presages the evolved ability to communicate with spoken language. The brain is large in Homo sapiens, who we know can speak, and relatively small in apes, who we know cannot speak (although they are capable of some symbolic communication). Homo erectus falls between the two in brain size. Could the erectus people who lived around Longgushan in the Pleistocene speak or not?

The size of the Homo erectus brain is estimated by anthropologists to have been between 950 and 1,200 cubic centimeters. Some modern people, known as microcephalics, have brains this small. Can they talk? The answers vary. Many microcephalics, if they survive infancy, are severely mentally retarded and have no effective use of spoken language.1 Others are normal. A rare few are even above normal. Anatole France, the nineteenth-century French author and playwright, had a very small brain (reportedly weighing 1,040 grams, which we can take as approximately equivalent to 1,040 cubic centimeters, and thus in the middle of the brain-size distribution for Homo erectus),2 but that fact somehow did not impair his fluent use of language. He was awarded the Nobel Prize for Literature in 1921. Brain size then, by itself, does not provide us with an ironclad argument for or against Homo erectuss capabilities for language.

Davidson Black first weighed in with his opinion that the anatomy, not the size of the Homo erectus brain, was evidence that the species could talk. By 1933, when Black published his opinion,3 he and his colleagues had gathered data that they believed showed that erectus hunted, used fire, and made a diversity of stone tools—behavior much like that of later humans in the archaeological record, such as Neandertals. Black pointed to the impressions made of the inside of the fossil skulls from Longgushan to infer the shape and form of the erectus brain. In particular he noted that the areas on the side of the brain in what would have been the frontal and temporal lobes seemed to be enlarged in Homo erectus, like in later humans and unlike in apes. This region of our brains contains language centers (termed "Broca's Area" or the inferior frontal gyrus, and "Wernicke's Area" or the superior temporal gyrus). As they have expanded in human evolution, these gyri have formed a prominent fold between them—the so-called Sylvian Fissure (also known as the lateral sulcus, separating the parietal and temporal lobes of the cerebrum). Black opined in 1933 that Homo erectus showed a humanlike form of the Sylvian Fissure and thus could speak. Many anthropologists since have tended to agree,4 despite their reservations about inferring such an important behavior from doubly indirect evidence—not only is the inside of the skull an imperfect reflection of the outside of the brain, but brains show quite a bit of variation from one to another. It is possible to have a chimp brain with a partial, humanlike

Fissure Rolando

Speech areas of the brain. The outside layers of the cerebral hemispheres of the human brain are known as the cerebral cortex. From studies of modern-day patients with brain injuries, two areas—Broca's Area in the frontal lobe and Wernicke's Area in the temporal lobe—are known to be essential for language production and comprehension. The Homo erectus brain was smaller and lower than modern humans' brains, suggesting that Broca's and Wernicke's Areas were not developed sufficiently for the species to speak in a human manner.

Speech areas of the brain. The outside layers of the cerebral hemispheres of the human brain are known as the cerebral cortex. From studies of modern-day patients with brain injuries, two areas—Broca's Area in the frontal lobe and Wernicke's Area in the temporal lobe—are known to be essential for language production and comprehension. The Homo erectus brain was smaller and lower than modern humans' brains, suggesting that Broca's and Wernicke's Areas were not developed sufficiently for the species to speak in a human manner.

Sylvian Fissure, as well as a human brain belonging to a well-spoken and fluent individual that shows only an incipient, apelike Sylvian Fissure. We cannot infer language ability with certainty from the brain endocasts of Homo erectus from Longgushan and other sites. Are there other anatomical clues that might tell us something about the species' ability to talk?

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Responses

  • saare
    Can homo erectus speak?
    8 years ago
  • eleanor
    Did homoerectus speak?
    2 years ago

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