Origin of language
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The origin of language, known in linguistics as glottogony, a technical term formed from the Greek roots of the same words, refers to the acquisition of the ability to use language by an earlier stage in the evolution of mankind. The term and the existence of the topic presume that Homo sapiens evolved from some non-human ancestor who did not possess language capabilities.
Understanding the origin of language, being both one of Homo sapiens' most complex, useful and consequential biological traits and one that distinguishes it from other species, poses difficulties, since, unlike writing, spoken language leaves no explicit concrete evidence of its nature or even its existence, requiring scientists resort to indirect methods. Given its importance and difficulty of investigation it is a topic that has attracted considerable attention and controversy throughout the entire debate on the validity of the descent of species since Charles Darwin first proposed it in the late 19th century. Linguists agree that there are no existing primitive languages and that all modern human populations speak languages of comparable complexity. While existing languages differ in terms of the size of and subjects covered by their lexicons, all possess the grammar and syntax necessary for communication and can invent, translate, or borrow the vocabulary necessary to express the full range of their speakers' concepts. All children possess the capacity to learn language and no child is born with a biological predisposition favoring any one language or type of language over another. There is no "half-language" that might shed light on its evolution.
The evolution of modern human language required both the development of the anatomical apparatus for speech and also neurological changes in the brain to support language itself, but other species have some of these capabilities without full language ability. The emergence of language use is tied to the full acquisition of these capabilities, but archaeological evidence does not provide an entirely clear picture of these events.
A major debate surrounding the emergence of language is whether language evolved slowly as these capabilities were acquired, resulting in a period of semi-language, or whether it emerged suddenly once all these capabilities were available.
Communication, speech and language
Many scientists make a distinction between speech and language. For instance, talking birds are able to imitate human speech with varying ability. However, this ability to mimic human sounds is very different from the acquisition of syntax. Likewise, the production of speech sounds is not necessary for language use, as evidenced by modern sign languages, which use manual gestures as a basis for language rather than speech.
The distinction between communication and language is also important. For instance, the communicative systems of vervet monkeys has been studied extensively. They are known to make up to ten different vocalizations. Many of these are used to warn other members of the group about approaching predators. They include a "leopard call", a "snake call", and an "eagle call", and each call triggers a different defensive strategy. However, these communications are in direct response to a stimulus in the immediate environment, and are not an instance of higher-level reference. Apes in captivity show similar communicative abilities, having been taught rudimentary sign language and the use of lexigrams—symbols that do not graphically resemble their corresponding words— and computer keyboards. Some apes, such as Kanzi, have been able to learn and use hundreds of lexigrams. However, while these apes are able to learn a basic syntactic and referential system, their communications lack the complexity of a full language.
A key feature that distinguishes between human language and non-human communication systems is recursion. Recursion is taking phrases, and using them as units, like in the sentence "(The man with the old crusty eyepatch he wore since WWII) walked to (the store that burned down before his uncle had put down the downpayment)", or the less informative "The man walked to the store which the man who walked to the store walked to". However, experimenters at the University of Chicago found that starlings (Sturnus vulgaris) can acquire a grammar with recursion. The experimenters trained starlings on a context-free, center-embedding grammar. They report that starlings were able to recognize utterances that were grammatically acceptable and reject those that were not. Moreover, Everett claims that Pirahã is a language without recursion. These findings pose a challenge for the argument that recursion is the distinguishing feature between human language and non-human communication systems.
Biological foundations for human language
The descended larynx was formerly viewed as a structure unique to the human vocal tract and essential to the development of speech and language. However, it has been found in other species, including some aquatic mammals and large deer (e.g. Red Deer), and the larynx has been observed to descend during vocalizations in dogs, goats, and alligators. In humans, the descended larynx extends the length of the vocal tract and expands the variety of sounds humans can produce. Some scholars claim that the ubiquity of nonverbal communication in humans stands as evidence of the non-essentiality of the descended larynx to the development of language.
The descended larynx has non-linguistic functions as well, possibly exaggerating the apparent size of an animal (through vocalizations with lower than expected pitch). Thus, although it plays an important role in speech production, expanding the variety of sounds humans can produce, it may not have evolved specifically for this purpose, and, as per Hauser, Chomsky, and Fitch (2002), could be an example of preadaptation.
Not much is known about great ape communication in the wild. The anatomical structure of their larynges does not enable apes to make many of the sounds that modern humans do. In captivity, apes have been taught rudimentary sign language and the use of lexigrams —symbols that do not graphically resemble their corresponding words— on computer keyboards. Some apes, such as Kanzi, have been able to learn and use hundreds of lexigrams.
The Broca's and Wernicke's areas in the primate brain are responsible for controlling the muscles of the face, tongue, mouth, and larynx, as well as recognizing sounds. Primates are known to make "vocal calls," and these calls are generated by circuits in the brainstem and limbic system.
In the wild, the communication of vervet monkeys has been the most extensively studied. They are known to make up to ten different vocalizations. Many of these are used to warn other members of the group about approaching predators. They include a "leopard call", a "snake call", and an "eagle call". Each call triggers a different defensive strategy in the monkeys that hear the call and scientists were able to elicit predictable responses from the monkeys using loudspeakers and prerecorded sounds. Other vocalizations may be used for identification. If an infant monkey calls, its mother turns toward it, but other vervet mothers turn instead toward that infant's mother to see what she will do.
There is considerable speculation about the language capabilities of ancient hominids. Anatomically, some scholars believe the advent of hominid bipedalism around 3.5 million years ago would have brought changes to the human skull, allowing for a more L-shaped vocal tract. The shape of the tract and a larynx positioned relatively low in the neck are necessary prerequisites for many of the sounds humans make, particularly vowels. Other scholars believe that, based on the position of the larynx, not even Neanderthals had the anatomy necessary to produce the full range of sounds modern humans make. Still another view considers the lowering of the larynx irrelevant to the development of speech.
An absolute proto-language, as defined by linguist Derek Bickerton, is a primitive form of communication lacking:
- a fully-developed syntax
- tense, aspect, auxiliary verbs, etc.
- a closed-class (i.e. non-lexical) vocabulary
That is, a stage in the evolution of language somewhere between great ape language and fully developed modern human language.
The term Hmmmmm has been proposed for the pre-linguistic system of communication used by archaic Homo (beginning with Homo ergaster and reaching the highest sophistification with Homo neanderthalensis. Hmmmmm is an acronym for holistic (non-compositional), manipulative (utterances are commands or suggestions, not descriptive statements), multi-modal (acoustic as well as gestural and mimetic), musical, and memetic.
Anatomical features such as the L-shaped vocal tract have been continuously evolving, as opposed to appearing suddenly. Hence it is most likely that archaic humans possessed some form of communication intermediate between that of modern humans and that of other primates.
The discovery in 2007 of a Neanderthal hyoid bone suggests that Neanderthals may have been anatomically capable of producing sounds similar to modern humans. By 400,000 years ago the hypoglossal canal of living hominids had reached the size of that in modern humans. The hypoglossal nerve, which passes through the canal, controls the movements of the tongue and its size is said to reflect speech abilities. Hominids who lived earlier than 300,000 years ago had hypoglossal canals more akin to those of chimpanzees than of humans.
However, although Neanderthals may have been anatomically able to speak, Richard G. Klein in 2004 doubted that they possessed a fully modern language. He largely bases his doubts on the fossil record of archaic humans and their stone tool kit. For 2 million years following the emergence of Homo habilis, the stone tool technology of hominids changed very little. Klein, who has worked extensively on ancient stone tools, describes the crude stone tool kit of archaic humans as impossible to break down into categories based on their function, and reports that Neanderthals seem to have had little concern for the final form of their tools. Klein argues that the Neanderthal brain may have not reached the level of complexity required for modern speech, even if the physical apparatus for speech production was well-developed. The issue of the Neanderthal's level of cultural and technological sophistication remains a controversial one.
Anatomically modern humans first appear in the fossil record 195,000 years ago in Ethiopia. But while they were modern anatomically, the archaeological evidence available leaves little indication that they behaved any differently from the hominids who existed before. They used the same relatively crude stone tools and hunted less efficiently than did modern humans within the past 164,000 years. However, beginning about 164,000 years ago in southern Africa, there is evidence of more sophisticated behavior (eating shellfish and other marine resources), and by 50,000 years ago, fully modern behavior is thought to have developed. At this point, a coastal lifestyle and the associated tool sophistication linked to shellfish consumption is evident. This lifestyle may have been a response to climatic habitat pressure due to Ice Age conditions. The stone tools that arose show regular patterns that are reproduced or duplicated with more precision. Later, other tools made of bone and antler appear as well. The artifacts are also now easily sortable into many different categories based on their function, such as projectile points, engraving tools, knife blades, and drilling and piercing tools. Teaching offspring or other group members how to manufacture such detailed tools would have been difficult without the aid of language.
The greatest step in language evolution would have been the progression from primitive, pidgin-like communication to a creole-like language with all the grammar and syntax of modern languages. Many scholars believe that this step could only have been accomplished with some biological change to the brain, such as a mutation. It has been suggested that a gene such as FOXP2 may have undergone a mutation allowing humans to communicate. Evidence suggests that this change took place somewhere in East Africa around 100,000 to 50,000 years ago, which rapidly brought about significant changes that are apparent in the fossil record. There is still some debate as to whether language developed gradually over thousands of years or whether it appeared suddenly.
The Broca's and Wernicke's areas of the brain also appear in the human brain, the first area being involved in many cognitive and perceptual tasks, the latter lending to language skills. The same circuits discussed in the primates brain stem and limbic system control non-verbal sounds in humans (laughing, crying, etc.), which suggests that the human language center is a modification of neural circuits common to "all" primates. This modification and its skill for linguistic communication seem to be unique only to humans, which implies that the language organ derived after the human lineage split from the primate (chimps and bonobos) lineage. Plainly stated, spoken language is a modification of the larynx that is unique to humans.
According to the Out of Africa hypothesis, around 50,000 years ago a group of humans left Africa and proceeded to colonize the rest of the world, including Australia and the Americas, which had never been populated by archaic hominids. Some scientists believe that Homo sapiens did not leave Africa before that, because they had not yet attained modern cognition and language, and consequently lacked the skills or the numbers required to migrate. However, given the fact that Homo erectus managed to leave the continent much earlier (without extensive use of language, sophisticated tools, nor anatomical modernity), the reasons why anatomically modern humans remained in Africa for such a long period remain unclear.
Cognitive development and language
One of the intriguing abilities that language users have is that of high-level reference, or the ability to refer to things or states of being that are not in the immediate realm of the speaker. This ability is often related to theory of mind, or an awareness of the other as a being like the self with individual wants and intentions. According to Chomsky, Hauser and Fitch (2002), there are six main aspects of this high-level reference system:
- Theory of mind
- Capacity to acquire nonlinguistic conceptual representations, such as the object/kind distinction
- Referential vocal signals
- Imitation as a rational, intentional system
- Voluntary control over signal production as evidence of intentional communication
- Number representation
Theory of mind
Simon Baron-Cohen (1999) argued that theory of mind must have preceded language use, based on evidence of use of the following characteristics as much as 40,000 years ago: intentional communication, repairing failed communication, teaching, intentional persuasion, intentional deception, building shared plans and goals, intentional sharing of focus or topic, and pretending. Moreover, Baron-Cohen argues that many primates show some, but not all, of these abilities. Call and Tomasello’s research on chimpanzees supports this, in that individual chimps seem to understand that other chimps have awareness, knowledge, and intention, but do not seem to understand false beliefs. Many primates show some tendencies toward a theory of mind, but not a full one as humans have.Ultimately, there is some consensus within the field that a theory of mind is necessary for language use. Thus, the development of a full theory of mind in humans was a necessary precursor to full language use.
In one particular study, rats and pigeons were required to press a button a certain number of times to get food: The animals showed very accurate distinction for numbers less than four, but as the numbers increased, the error rate increased (Chomsky, Hauser & Fitch, 2002). Matsuzawa (1985) attempted to teach chimpanzees Arabic numerals. The difference between primates and humans in this regard was very large, as it took the chimps thousands of trials to learn 1-9, and they then had significant difficulty with larger numbers; yet in children, after learning 1-9, their number use becomes much more complex very quickly, and with relative ease.
Since children are largely responsible for creolization of a pidgin, scholars such as Derek Bickerton and Noam Chomsky concluded that humans are born with a universal grammar hardwired into their brains. This universal grammar consists of a wide range of grammatical models that include all the grammatical systems of the world's languages. The default settings of this universal grammar are represented by the similarities apparent in creole languages. These default settings are overridden during the process of language acquisition by children to match the local language. When children learn language, they first learn the creole-like features more easily than the features that conflict with creole grammar.
An issue often cited as support for the Universal grammar theory is the development of Nicaraguan Sign Language. Beginning in 1979, the recently installed Nicaraguan government initiated the country's first widespread effort to educate deaf children. Prior to this there was no deaf community in the country. A center for special education established a program initially attended by 50 young deaf children. By 1983 the center had 400 students. The center did not have access to teaching facilities of any of the sign languages that are used around the world; consequently, the children were not taught any sign language. The language program instead emphasized spoken Spanish and lipreading, and the use of signs by teachers limited to fingerspelling (using simple signs to sign the alphabet). The program achieved little success, with most students failing to grasp the concept of Spanish words.
The first children who arrived at the center came with only a few crude gestural signs developed within their own families. However, when the children were placed together for the first time they began to build on one another's signs. As more younger children joined the language became more complex. The children's teachers, who were having limited success at communicating with their students, watched in awe as the kids began communicating amongst themselves.
Later the Nicaraguan government solicited help from Judy Kegl, an American sign-language expert at Northeastern University. As Kegl and other researchers began to analyze the language, they noticed that the young children had taken the pidgin-like form of the older children to a higher level of complexity, with verb agreement and other conventions of grammar (but no recursion).
Hockett (1966) details a list of features regarded as essential to describing human language. In the domain of the lexical-phonological principle, two features of this list are most important:
- Productivity: users can create and understand completely novel messages.
- New messages are freely coined by blending, analogizing from, or transforming old ones.
- Either new or old elements are freely assigned new semantic loads by circumstances and context. This says that in every language, new idioms constantly come into existence.
- Duality (of Patterning): a large number of meaningful elements are made up of a conveniently small number of independently meaningless yet message-differentiating elements.
The sound system of a language is composed of a finite set of simple phonological items. Under the specific phonotactic rules of a given language, these items can be recombined and concatenated, giving rise to morphology and the open-ended lexicon. A key feature of language is that a simple, finite set of phonological items gives rise to an infinite lexical system wherein rules determine the form of each item, and meaning is inextricably linked with form. Phonological syntax, then, is a simple combination of pre-existing phonological units. Related to this is another essential feature of human language: lexical syntax, wherein pre-existing units are combined, giving rise to semantically novel or distinct lexical items.
Certain elements of the lexical-phonological principle are known to exist outside of humans. While all (or nearly all) have been documented in some form in the natural world, very few co-exist within the same species. Birdsong, singing apes, and the songs of whales all display phonological syntax, combining units of sound into larger structures devoid of enhanced or novel meaning. Certain species of primate do have simple phonological systems with units referring to entities in the world. However, in contrast to human systems, the units in these primates' systems normally occur in isolation, betraying a lack of lexical syntax. There is new evidence to suggest that Campbell's monkeys also display lexical syntax, combining two calls (a predator alarm call with a "boom", the combination of which denotes a lessened threat of danger), however it is still unclear whether this is a lexical or a morphological phenomenon.
Pidgins and creoles
Pidgins are significantly simplified languages with only rudimentary grammar and a restricted vocabulary. In their early stage pidgins mainly consist of nouns, verbs, and adjectives with few or no articles, prepositions, conjunctions or auxiliary verbs. Often the grammar has no fixed word order and the words have no inflection.
If contact is maintained between the groups speaking the pidgin for long periods of time, the pidgins may become more complex over many generations. If the children of one generation adopt the pidgin as their native language it develops into a creole language, which becomes fixed and acquires a more complex grammar, with fixed phonology, syntax, morphology, and syntactic embedding. The syntax and morphology of such languages may often have local innovations not obviously derived from any of the parent languages.
Studies of creole languages around the world have suggested that they display remarkable similarities in grammar and are developed uniformly from pidgins in a single generation. These similarities are apparent even when creoles do not share any common language origins. In addition, creoles share similarities despite being developed in isolation from each other. Syntactic similarities include Subject Verb Object word order. Even when creoles are derived from languages with a different word order they often develop the SVO word order. Creoles tend to have similar usage patterns for definite and indefinite articles, and similar movement rules for phrase structures even when the parent languages do not.
Scenarios for language evolution
Linguistic monogenesis is the hypothesis that there was a single proto-language, sometimes called Proto-Human, from which all other languages spoken by humans descend. All human populations possess language. This includes populations, such as the Tasmanians and the Andamanese, who may have been isolated from the Old World continents for as long as 40,000 years. Thus, the multiregional hypothesis would entail that modern language evolved independently on all the continents, a proposition considered implausible by proponents of monogenesis.
According to the Out of Africa hypothesis, all humans alive today are descended from Mitochondrial Eve, a woman estimated to have lived in Africa some 150,000 years ago. This raises the possibility that the Proto-Human language could date to approximately that period. There are also claims of a population bottleneck, notably the Toba catastrophe theory, which postulates human population at one point some 70,000 years ago was as low as 15,000 or even 2,000 individuals. If it indeed transpired, such a bottleneck would be an excellent candidate for the date of Proto-Human, which also illustrates the fact that Proto-Human would not necessarily date to the first emergence of language.
The gestural theory states that human language developed from gestures that were used for simple communication.
Two types of evidence support this theory.
- Gestural language and vocal language depend on similar neural systems. The regions on the cortex that are responsible for mouth and hand movements border each other.
- Nonhuman primates can use gestures or symbols for at least primitive communication, and some of their gestures resemble those of humans, such as the "begging posture", with the hands stretched out, which humans share with chimpanzees.
Research found strong support for the idea that verbal language and sign language depend on similar neural structures. Patients who used sign language, and who suffered from a left-hemisphere lesion, showed the same disorders with their sign language as vocal patients did with their spoken language. Other researchers found that the same left-hemisphere brain regions were active during sign language as during the use of vocal or written language.
The important question for gestural theories is why there was a shift to vocalization. There are three likely explanations:
- Our ancestors started to use more and more tools, meaning that their hands were occupied and could not be used for gesturing.
- Gesturing requires that the communicating individuals can see each other. There are many situations in which individuals need to communicate even without visual contact, for instance when a predator is closing in on somebody who is up in a tree picking fruit.
- The need to co-operate effectively with others in order to survive. A command issued by a tribal leader to 'find' 'stones' to 'repel' attacking 'wolves' would create teamwork and a much more powerful, co-ordinated response.
Humans still use hand and facial gestures when they speak, especially when people meet who have no language in common. There are also, of course, a great number of sign languages still in existence, commonly associated with Deaf communities.
The search for the origin of language has a long history rooted in mythology.
In religion and mythology
Religions and ethnic mythologies often provide explanations for the origin and development of language. Most mythologies do not credit humans with the invention of language but know of a divine language predating human language. Mystical languages used to communicate with animals or spirits, such as the language of the birds, are also common, and were of particular interest during the Renaissance.
History contains a number of anecdotes about people who attempted to discover the origin of language by experiment. The first such tale was told by Herodotus. He relates that Pharaoh Psammetichus (probably Psammetichus I) had two children raised by deaf-mutes in order to see what language they would speak. When the children were brought before him, one of them said something that sounded to the Pharaoh like bekos, the Phrygian word for bread. From this Psammetichus concluded that the first language was Phrygian. King James V of Scotland is said to have tried a similar experiment: his children were supposed to have spoken Hebrew. Both the medieval monarch Frederick II and Akbar, a 16th century Mughal emperor of India, are said to have tried similar experiments; the children involved in these experiments did not speak.
History of research
Late 18th to early 19th century European scholarship assumed that the languages of the world reflected various stages in the development from primitive to advanced speech, culminating in the Persian language, seen as the most advanced. Modern linguistics does not begin until the late 18th century, and the Romantic or animist theses of Johann Gottfried Herder and Johann Christoph Adelung remained influential well into the 19th century. The question of language origins seemed inaccessible to methodical approaches, and in 1866 the Linguistic Society of Paris famously banned all discussion of the origin of language, deeming it to be an unanswerable problem. An increasingly systematic approach to historical linguistics developed in the course of the 19th century, reaching its culmination in the Neogrammarian school of Karl Brugmann and others. However, scholarly interest in the question of the origin of language has only gradually been rekindled from the 1950s on (and then controversially) with ideas such as Universal grammar, mass comparison and glottochronology. The "origin of language" as a subject in its own right emerged out of studies in neurolinguistics, psycholinguistics and human evolution. The Linguistic Bibliography introduced "Origin of language" as a separate heading in 1988, as a sub-topic of psycholinguistics. Dedicated research institutes of evolutionary linguistics are a recent phenomenon, emerging only in the 1990s.
- ^ "glottogony". dictionary.com. http://dictionary.reference.com/browse/glottogony.
- ^ Salingaros, Nikos A.; Mehaffy, Michael W. (2006). A theory of architecture. Solingen: Umbau-Verlag. p. 229.
- ^ Pinker, Steven (2000). The Language Instinct: How the Mind Creates Language. New York: Harper Perennial Modern Classics. pp. 13–14. ISBN 0-060-95833-2.
- ^ a b Aronoff, Mark; Rees-Miller, Janie, eds (2001). The Handbook of Linguistics. Oxford: Blackwell Publishers. pp. 1-18. ISBN 1405102527.
- ^ Hauser 2002.
- ^ Gentner, Timothy Q.; Fenn, Kimberley M.; Margoliash, Daniel; Nusbaum, Howard C. (27 April 2006). Nature 440 (7088): 1204-1207.
- ^ Everett, Daniel L. (August–October 2005). "Cultural Constraints on Grammar and Cognition in Pirahã: Another Look at the Design Features of Human Language". Current Anthropology 46 (4): 634. http://www.eva.mpg.de/psycho/pdf/Publications_2005_PDF/Commentary_on_D.Everett_05.pdf.
- ^ a b Freeman, Scott; Jon C. Herron., Evolutionary Analysis (4th ed.), Pearson Education, Inc. (2007), ISBN 0-13-227584-8 pages 789-90
- ^ a b c d e f Diamond, Jared (1992, 2006). The Third Chimpanzee: The Evolution and Future of the Human Animal. New York: Harper Perennial. pp. 141–167. ISBN 0060183071.
- ^ Wade, Nicholas (2006-05-23). "Nigerian Monkeys Drop Hints on Language Origin". The New York Times. http://www.nytimes.com/2006/05/23/science/23lang.html?ex=1306036800&en=7012db68d9bb1cc5&ei=5088&partner=rssnyt&emc=rss. Retrieved 2007-09-09.
- ^ Fitch, W. Tecumseh. "The Evolution of Speech: A Comparative Review" (PDF). http://www3.isrl.uiuc.edu/~junwang4/langev/localcopy/pdf/fitch00speech.pdf. Retrieved 2007-09-09.
- ^ Ohala, John J.. (2000). The irrelevance of the lowered larynx in modern man for the development of speech. In Evolution of Language - Paris conference (pp. 171-172).
- ^ [[Steven Mithen |Mithen, Steven J.]] (2006). The Singing Neanderthals: The Origins of Music, Language, Mind, and Body. Cambridge: Harvard University Press. ISBN 0-674-02192-4.
- ^ Olson, Steve (2002). Mapping Human History. Houghton Mifflin Books. ISBN 0618352104. "Any adaptations produced by evolution are useful only in the present, not in some vaguely defined future. So the vocal anatomy and neural circuits needed for language could not have arisen for something that did not yet exist"
- ^ Ruhlen, Merritt (1994). Origin of Language. New York, NY: Wiley. p. 3. ISBN 0471584266. "Earlier human ancestors, such as Homo habilis and Homo erectus, would likely have possessed less developed forms of language, forms intermediate between the rudimentary communicative systems of, say, chimpanzees and modern human languages"
- ^ Jungers, William L. et al. (August 2003). "Hypoglossal Canal Size in Living Hominoids and the Evolution of Human Speech" (PDF). Human Biology 75 (4): 473–484. doi:10.1353/hub.2003.0057. http://www.baa.duke.edu/kay/site/riogallegos/PDFs/j74.pdf. Retrieved 2007-09-10.
- ^ DeGusta, David et al. (1999). "Hypoglossal Canal Size and Hominid Speech". Proceedings of the National Academy of Sciences of the United States of America 96 (4): 1800–1804. doi:10.1073/pnas.96.4.1800. PMID 9990105. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=15600%094. Retrieved 2007-09-10. "Hypoglossal canal size has previously been used to date the origin of human-like speech capabilities to at least 400,000 years ago and to assign modern human vocal abilities to Neandertals. These conclusions are based on the hypothesis that the size of the hypoglossal canal is indicative of speech capabilities.".
- ^ Johansson, Sverker (April 2006). "Constraining the Time When Language Evolved" (PDF). Evolution of Language: Sixth International Conference, Rome: 152. doi:10.1142/9789812774262_0020. http://www.tech.plymouth.ac.uk/socce/evolang6/johansson_constraining.pdf. Retrieved 2007-09-10. "Hyoid bones are very rare as fossils, as they are not attached to the rest of the skeleton, but one Neanderthal hyoid has been found (Arensburg et al., 1989), very similar to the hyoid of modern Homo sapiens, leading to the conclusion that Neanderthals had a vocal tract similar to ours (Houghton, 1993; Bo¨e, Maeda, & Heim, 1999).".
- ^ a b Klarreich, Erica (April 20, 2004). "Biography of Richard G. Klein". Proceedings of the National Academy of Sciences of the United States of America 101 (16): 5705–5707. doi:10.1073/pnas.0402190101. PMID 15079069. http://www.pnas.org/cgi/content/full/101/16/5705#SEC1. Retrieved 2007-09-10.
- ^ Klein, Richard G.. "Three Distinct Human Populations". Biological and Behavioral Origins of Modern Humans. Access Excellence @ The National Health Museum. http://www.accessexcellence.org/BF/bf02/klein/bf02e3.html. Retrieved 2007-09-10.
- ^ a b Schwarz, J. http://uwnews.org/article.asp?articleID=37362
- ^ quote "Our findings show that at 164,000 years ago in coastal South Africa humans expanded their diet to include shellfish and other marine resources, perhaps as a response to harsh environmental conditions," said Curtis Marean, a paleoanthropologist with the Institute of Human Origins at Arizona State University who headed the research team "This is the earliest dated observation of this behavior" Schwarz, J. http://uwnews.org/article.asp?articleID=37362
- ^ Wolpert, Lewis (2006). Six impossible things before breakfast, The evolutionary origins of belief. New York: Norton. p. 81. ISBN 0393064492. http://books.google.com/books?id=HP35qPdfioAC&pg=PA81&dq=%22make+complex+tools+in+fact%22&ei=G-JsSJ3GI4GkjgH1kuTEAg&sig=ACfU3U3eJ7l7tKIdZJPHQ0SeD3I7T_AYsQ.
- ^ Minkel, J. R. (2007-07-18). "Skulls Add to "Out of Africa" Theory of Human Origins: Pattern of skull variation bolsters the case that humans took over from earlier species". Scientific American.com. http://www.sciam.com/article.cfm?articleID=DA5114C2-E7F2-99DF-30BBDDD4415DED90. Retrieved 2007-09-09.
- ^ Klein, Richard. "Three Distinct Populations". http://www.accessexcellence.org/BF/bf02/klein/bf02e3.html. Retrieved 2007-11-10. "You've had modern humans or people who look pretty modern in Africa by 100,000 to 130,000 years ago and that's the fossil evidence behind the recent "Out of Africa" hypothesis, but that they only spread from Africa about 50,000 years ago. What took so long? Why that long lag, 80,000 years?"
- ^ A Linguistic Big Bang
- ^ Wade, Nicholas (2003-07-15). "Early Voices: The Leap to Language". The New York Times. http://query.nytimes.com/gst/fullpage.html?res=9503E0DF173CF936A25754C0A9659C8B63&sec=health&spon=&pagewanted=1. Retrieved 2007-09-10.
- ^ Sverker, Johansson. "Origins of Language - Constraints on Hypotheses" (PDF). http://www.arthist.lu.se/kultsem/pro/SverkerJohansson-sem.pdf. Retrieved 2007-09-10.
- ^ Ruhlen, Merritt (1996). "Language Origins". National Forum. http://findarticles.com/p/articles/mi_qa3651/is_199601/ai_n8757319/pg_1. Retrieved 2007-11-10.
- ^ Whitehouse, David (2003-06-09). "When Humans Faced Extinction". BBC News Online. http://news.bbc.co.uk/1/hi/sci/tech/2975862.stm. Retrieved 2007-11-10.
- ^ Premack, David & Premack, Ann James. The Mind of an Ape, ISBN 0-393-01581-5.
- ^ Kimura, Doreen (1993). Neuromotor Mechanisms in Human Communication. Oxford: Oxford University Press. ISBN 978-0-19-505492-7.
- ^ Newman, A. J., et al. (2002). [Expression error: Missing operand for > "A Critical Period for Right Hemisphere Recruitment in American Sign Language Processing"]. Nature Neuroscience 5: 76–80. doi:10.1038/nn775.
- ^ Kolb, Bryan, and Ian Q. Whishaw (2003). Fundamentals of Human Neuropsychology (5th ed.). Worth Publishers. ISBN 978-0716753001.
- ^ Re: Did hitler experiment with babies
- ^ Linguistics 201: First Language Acquisition
- Allott, Robin (1989). The Motor Theory of Language Origin. Sussex, England: Book Guild. ISBN 0-86332-359-6.
- Botha, R. and C. Knight (2009). The Prehistory of Language. Oxford: Oxford University Press. ISBN 9780199545872.
- Botha, R and C. Knight (2009). The Cradle of Language. Oxford: Oxford University Press. ISBN 9780199545858.
- Cangelosi, A., A. Greco, and Stevan Harnad. (2002) "Symbol grounding and the symbolic theft hypothesis." Simulating the Evolution of Language, edited by A. Cangelosi and D. Parisi. London: Springer.
- Crystal, David (1997). The Cambridge Encyclopedia of Language. Cambridge: Cambridge University Press. ISBN 0-521-55967-7.
- Dawkins, Richard. 2004. The Ancestor's Tale: A Pilgrimage to the Dawn of Life. London: Weidenfeld and Nicolson.
- Deacon, Terrence William (1997). The Symbolic Species: The Co-evolution of Language and the Brain. New York: W.W. Norton. ISBN 0-393-03838-6.
- Dunbar, R.I.M. (1996). Grooming, Gossip and the Evolution of Language. London: Faber and Faber. ISBN 0-571-17396-9.
- Givón, T. (2002). "The evolution of language out of pre-language." Typological studies in language 53. Amsterdam: John Benjamins. ISBN 1-58811-237-3.
- Harnad, S.R., J. B. Lancaster, and H.D. Steklis (1976). Origins and Evolution of Language and Speech. New York: New York Academy of Sciences. ISBN 0890720266.
- Hauser, Marc D.; Chomsky, Noam; Fitch, W. Tecumseh (2002). [Expression error: Missing operand for > "The faculty of language: What is it, who has it, and how did it evolve?"]. Science 298 (5598): 1569-1579.
- Hurford, James R. (1990). "Nativist and functional explanations in language acquisition." Logical Issues in Language Acquisition, edited by I.M. Roca, 85–136. Dordrecht: Foris. ISBN 9067655066.
- Kenneally, Christine (2007). The First Word: The Search for the Origins of Language. New York: Viking.
- Knight, C., M. Studdert-Kennedy and J. R. Hurford (eds), 2000. The Evolutionary Emergence of Language. Cambridge: Cambridge University Press.
- Komarova, N.L. (2007). "Language and mathematics: An evolutionary model of grammatical communication." History & Mathematics, edited by Leonid Grinin, Victor C. de Munck, and Andrey Korotayev, 164–179. Moscow: KomKniga/URSS. ISBN 9785484010011.
- Logan, Robert. (2007). The Extended Mind: The Emergence of Language, the Human Mind and Culture. Toronto: Univ. of Toronto Press.
- Pollick, Amy. S and Frans B.M. de Waal (2007). "Ape gestures and language evolution." Proceedings of the National Academy of Sciences 104.19, 8184–8189. (Also: Popular summary by Liz Williams, "Human language born from ape gestures", Cosmos, May 1, 2007.)
- Saussure, Ferdinand de (1986). Course in General Linguistics, translated by Roy Harris. Chicago: Open Court. (English translation of 1972 edition of Cours de linguistique générale, originally published in 1916.)
- Vajda, Edward. "The origin of language."
- Language and Social Organization
- The recent origin of human speech
- Lieberman, P. (2007). The evolution of human speech: Its anatomical and neural bases. Current Anthropology, 48(1), 39-66.