Shane McConnel
Dr. Robert D. McCall
ANT 320-01
Human Origins
December 11, 2000

Virtually all animals communicate with conspecifics—other members of the same species. Whales sing to one another across the oceans. Bees dance to direct other members of the hive to food. Birds initiate courtship with particular calls. Fireflies bioluminesce for mating purposes. However, humans are the only animals that utilise speech to communicate information about themselves, the environment, abstract thoughts, or the happenings of the past and future. Human males and females appropriate language at an early age and it stays with them their whole lives. Scientists understand the mechanism behind this but have yet to fathom how or why it developed or became advantageous in the course of human evolution. Why natural selection favoured anatomical and neurological alterations that enhanced humans' ancestors' ability to use spoken language is not yet known. However, this trend would not have been possible if early hominins had not been predisposed to language development.

Anthropologists cannot begin to pinpoint exactly when hominins first began using language because its development was most certainly gradual. However, it has been hypothesised that "the processÉ [began] when [hominins] started making and using tools. If early hominins at first depended on gestures to communicate, such hand signals would no doubt have eventually become inadequate; the hominins might literally have had their hands full, carrying tools or food. Thus the ability to use sounds voluntarily to attract attention and to make meaning clear would have proved a great advantage" (Campbell 2000). David Premack, however, fails to see how language might have been advantageous to early hominins: "Language evolved, it is conjectured, at a time when humans or protohumans were hunting mastodonsÉWould it be a great advantage for one of our ancestors squatting alongside the embers, to be able to remark: 'Beware of the short beast whose front hoof Bob cracked when, having forgotten his spear back at camp, he got in a glancing blow with the dull spear he borrowed from Jack'?" (Pinker 1995). Leslie Aiello and Robin Dunbar, based on correlations between primate brain size and group size, suggest that "as [hominin] groups continued to grow, they eventually reached the size where grooming was no longer viable as the main way of coordinating and servicing the expanding number of social relationships. At about the point where 25 to 30 percent of the day would have been needed for enough physical grooming to ensure group cohesion, time budget constraints should have selected for some other form of social lubrication... language first evolved as that social lubricant, a form of vocal grooming that facilitated the maintenance of large groups" (Campbell 2000).

Obviously, there is no consensus on why language might have evolved in hominins. However, no matter why language first evolved, it was first necessary that the vocal apparatus be modified and that the brain evolve.

Vocalisations of nonhuman primates are not completely controlled by the motor cortex, "the outer layer [of the brain]... composed of nerve cells or neurons... pertaining to outgoing signals involved in muscle use" (Jurmain 1997). Some of the regions of the brain directly involved in human speech production are located in the motor cortex and direct the movement of the mouth, larynx, and tongue. Only these particular movements are involved in language. "Damage to these neural tracts does not cause paralysis (as damage to other areas will do), but it will disturb speech, demonstrating that these structures are adapted to movements related specifically to speech production" (Jurmain 1997).

The areas of the human cerebral cortex most commonly and frequently associated with language and speech are termed Broca's and Wernicke's areas. They are involved in "the hierarchical organisation of grammar and the manual combination of objects" (Campbell 2000) and "comprehending and producing meaningful speech" (Campbell 2000), respectively. "A nearly complete [Homo erectus (ergaster)] skeleton from West Turkana (WT-15000), about 1.6 million years oldÉ possesses an impression of Broca's area" (Staski 1992) in its skullcap. Impressions on endocasts of fissures in the area of the frontal lobe of Homo (Australopithecus) habilis have also been observed. We do not know, however, if habilines used these areas for language, because even monkeys have a small homologue to Broca's area. It is easier to imagine that the language area in Homo erectus contributed to its great success in taming fire, crafting symmetrical hand axes, and moving across much of the Old World. None of these particular similarities to modern humans have been found in australopiths.

Interrelated are the position of the larynx with respect to the throat and the degree of flexion of the cranial base. Adult modern humans have a larynx low in the throat, "a position that allows the throat to serve as a resonating chamber capable of a greater number of sounds" (Relethford 1997). However, because the larynx is soft tissue it decomposes. Because it does not fossilise scientists are forced to get clues about the position of the larynx by looking at the base of the cranium. Degree of flexion of the cranial base is directly related to laryngeal position because "it shapes the roof of the voice box" (Klein 1999). "Laitman and colleagues (1979) investigated the crania of a number of fossil [hominins] and concluded that, whereas Australopithecus has the ape pattern, the crania of many archaic H. sapiens are more similar to modern-day humans. The Neandertals (Homo neanderthalensis) had a pattern that was between those of a modern subadult and modern adult human, suggesting that their language abilities may have been somewhat different" (Relethford 1997) from modern humans. Full basicranial flexion similar to that found in modern sapiens is not found before Homo heidelbergensis, dated from 800,000 to 100,000 years before the present.

One of the reasons chimpanzees cannot speak is because their oral cavity is much too long and thus prevents the production of consonant sounds in their vocalisations. Because this cavity is shaped so much differently, lingual musculature is different as well. The position of the hyoid bone provides clues as to the orientation of muscles because it serves as a site of attachment for one of the muscles of the tongue. It is higher and farther back in modern humans than it is in apes and presumably early hominins. This high position in modern sapiens allows for precise and efficient control of the tongue. Furthermore, an elongated oral cavity disallows the tongue from reaching particular contact points necessary for the creation of consonant sounds. "Measurements of the oral cavities of Homo erectus and Neandertal fossil skulls fall close to or into the human range and distinguish them clearly from the chimpanzee" (Campbell 2000). This seems to imply that these particular hominins had some capacity for lucid speech.

The above findings have been reinforced by research into the hypoglossal canal of hominins. This canal allows for the passage of the hypoglossal nerve to the musculature of the tongue. "Specimens of Australopithecus africanus, and possibly Homo (Austraolpithecus) habilis, were found to be similar to apes with regard to hypoglossal canal size, and both early [hominin] types had significantly smaller canals than modern humans. In contrast, the hypoglossal canals of Neandertal and Homo heidelbergensis people had reached modern size, suggesting that modern vocal capacities may have begun in the middle Pleistocene, well before the appearance of Homo sapiens" (Campbell 2000).

In studying the Nariokotome boy, the most complete Homo erectus skeleton found to date, it has been found that the neural canal of thoracic vertebrae is quite small compared to modern humans. This small canal "argues for reduced size of the spinal cord, which in turn may suggest less control of the muscles between the ribs (the intercostals)" (Jurmain 1997). These muscle groups "provide the power for speech production" (Jones 1992) by allowing for precise control of breathing while speaking. The only conclusion that may be drawn from this is that Homo erectus was not fully capable of articulate speech.

It is both interesting and amusing to note that the only concrete evidence there is of spoken language is only a little more than one hundred years old, going back to the earliest voice recordings of Thomas Alva Edison. However, we can rightly assume that language has existed for several hundred millennia. It seems quite fair to state Australopiths and early Homo were not capable of language as modern humans know it. The language capabilities of Homo erectus are questionable because it appears to have possessed the proper neural modifications for speech but was lacking in many of the other anatomical specialisations necessary for speech production. Therefore, it would seem that hominin specimens living after 400,000 years B.P. are the best candidates for having had the potential for somewhat modern language abilities.

But perhaps the question plaguing the minds of many individuals is: Could Neandertals (Homo neanderthalensis) speak? Actually, no one denies the Neandertal ability to speak. The real question is whether or not they were able to form all the vowels and consonants of modern human languages. Linguist Philip Lieberman asserts that the Neandertal larynx was located high in the vocal tract much like non-human primates. He argues that this is evidenced by the flat structure of the basicranium, and also points out that "the Neandertal oral cavity (the distance from the teeth to the back of the mouth) was greater than ours. Following the logic of this reconstruction, had the tongue and vocal tract been configured as in modern humans, the larynx, because of the oral cavity's large size, would have been located in the chest! Such a position is unknown in any animal species. Therefore, concludes Lieberman, Neandertals could not have had the same positioning of the tongue and other structure of the vocal tract as seen in modern humans, and this differently arranged vocal tract could not have formed the vowels 'i', as in tea; 'u', as in too; and 'a', as in tall; or the consonants 'k' and 'g', as in Kate and gate" (Jurmain 1997). "In any case, e lengeege weth e smell nember ef vewels cen remeen quete expresseve, so we cannot conclude that a [hominin] with a restricted vowel space had little language" (Pinker 1995).

More recent investigations into the basicrania of Neandertals have illustrated that they are "just as, if not even more, flexed than those of anatomically modern humans" (Jurmain 1997), suggesting that they could make the full range of modern human sounds. Studies have also shown that Neandertals possessed an enlarged canal in the thoracic vertebrae, "implying refined nervous control over phonetically significant movements of the rib cage" (Klein 1999).

However, there are those that argue for the recent advent of language, not until at most 60,000 years B.P., well into the reign of anatomically modern Homo sapiens. Those arguing this point use the archaeological record as their source of information and focus on "cultural innovations, such as bone tools and cave art" (Relethford 1997).

Campbell, Bernard G. and James D. Loy. Humankind Emerging Eighth Edition. United States of America: Allyn and Bacon, 2000. pp. 355, 428, 429, 430, 436-437.

Jurmain, Robert, Harry Nelson, Lynn Kilgore, and Wenda Trevathan. Introduction to Physical Anthropology Seventh Edition. Cincinatti: Wadsworth Publishing Company, 1997. pp. 274, 275, 417, 465.

Jones, Steve, Robert Martin, and David Pilbeam, eds. The Cambridge Encyclopedia of Human Evolution. Italy: Cambridge University Press, 1992. pp. 134.

Klein, Richard G. The Human Career: Human Biological and Cultural Origins Second Edition. Chicago: The University of Chicago Press, 1999. pp. 207, 392.

Pinker, Steven. The Language Instinct: How Mind Creates Language. United States of America: HarperPerennial, 1995. pp. 354, 366-367.

Relethford, John H. The Human Species: An Introduction to Biological Anthropology Third Edition. United States of America: Mayfield Publishing Company, 1997. pp. 344, 355.

Staski, Edward, and Jonathan Marks. Evolutionary Anthropology: An Introduction to Physical Anthropology and Archaeology. Philadelphia: Harcourt Bruce Jovanovich College Publishers, 1992. pp. 449.