Editing Origin of language (section)

=== Gestural theory ===
The gestural theory states that human language developed from [[gesture]]s 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 [[Cerebral cortex|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.<ref>Premack, David & Premack, Ann James. ''The Mind of an Ape'', {{ISBN|0-393-01581-5}}.</ref><ref>{{Cite journal |last1=Pollick |first1=A. S. |last2=de Waal |first2=F. B. |date=May 2007 |title=Ape Gestures and Language Evolution |journal=Proceedings of the National Academy of Sciences |volume=104 |issue=19 |pages=8184–8189 |bibcode=2007PNAS..104.8184P |doi=10.1073/pnas.0702624104 |pmc=1876592 |pmid=17470779 |doi-access=free}}</ref>

Research has found strong support for the idea that [[oral communication]] and sign language depend on similar neural structures. Patients who used sign language, and who suffered from a left-[[Cerebral hemisphere|hemisphere]] [[lesion]], showed the same disorders with their sign language as vocal patients did with their oral language.<ref>{{Cite book |last=Kimura |first=Doreen |title=Neuromotor mechanisms in human communication |publisher=Oxford University Press |year=1993 |isbn=978-0-19-505492-7 |location=New York}}</ref> Other researchers found that the same left-hemisphere brain regions were active during sign language as during the use of vocal or written language.<ref>{{Cite journal |last=Newman |first=A. J. |display-authors=etal |year=2002 |title=A Critical Period for Right Hemisphere Recruitment in American Sign Language Processing |journal=Nature Neuroscience |volume=5 |issue=1 |pages=76–80 |doi=10.1038/nn775 |pmid=11753419 |s2cid=2745545}}</ref>

Primate gesture is at least partially genetic: different nonhuman apes will perform gestures characteristic of their species, even if they have never seen another ape perform that gesture. For example, gorillas beat their breasts. This shows that gestures are an intrinsic and important part of primate communication, which supports the idea that language evolved from gesture.<ref name="Arbib2008">{{Cite journal |last1=Arbib |first1=M. A. |last2=Liebal |first2=K |last3=Pika |first3=S. |date=December 2008 |title=Primate vocalization, gesture, and the evolution of human language |journal=Current Anthropology |volume=49 |issue=6 |pages=1053–1076 |doi=10.1086/593015 |pmid=19391445 |s2cid=18832100}}</ref>

Further evidence suggests that gesture and language are linked. In humans, manually gesturing has an effect on concurrent vocalizations, thus creating certain natural vocal associations of manual efforts. Chimpanzees move their mouths when performing fine motor tasks. These mechanisms may have played an evolutionary role in enabling the development of intentional vocal communication as a supplement to gestural communication. Voice modulation could have been prompted by preexisting manual actions.<ref name="Arbib2008" />

From infancy, gestures both supplement and predict speech.<ref>{{Cite journal |last1=Capone |first1=Nina C. |last2=McGregor |first2=Karla K. |year=2004 |title=Gesture Development |journal=Journal of Speech, Language, and Hearing Research |volume=47 |issue=1 |pages=173–186 |doi=10.1044/1092-4388(2004/015) |pmid=15072537 |s2cid=7244799}}</ref><ref>{{Cite journal |last1=Ozçalişkan |first1=S. |last2=Goldin-Meadow |first2=S. |date=July 2005 |title=Gesture is at the cutting edge of early language development |journal=Cognition |volume=96 |issue=3 |pages=B101–B113 |doi=10.1016/j.cognition.2005.01.001 |pmid=15996556 |s2cid=206863317}}</ref> This addresses the idea that gestures quickly change in humans from a sole means of communication (from a very young age) to a supplemental and predictive behavior that is used despite the ability to communicate verbally. This too serves as a parallel to the idea that gestures developed first and language subsequently built upon it.

Two possible scenarios have been proposed for the development of language,<ref name="Rizzolatti">Rizzolatti, G. (2008). Giacomo Rizzolatti on the Evolution of Language. Retrieved from http://gocognitive.net/interviews/evolution-language-gestures{{full citation needed|date=January 2015}}</ref> one of which supports the gestural theory:
# Language developed from the calls of human ancestors.
# Language was derived from gesture.
The first perspective that language evolved from the calls of human ancestors seems logical because both humans and animals make sounds or cries. One evolutionary reason to refute this is that, anatomically, the centre that controls calls in monkeys and other animals is located in a completely different part of the brain than in humans. In monkeys, this centre is located in the depths of the brain related to emotions. In the human system, it is located in an area unrelated to emotion. Humans can communicate simply to communicate—without emotions. So, anatomically, this scenario does not work.<ref name="Rizzolatti" /> This suggests that language was derived from gesture<ref name="Kendon2017">{{Cite journal |last=Kendon |first=Adam |date=February 2017 |title=Reflections on the "gesture-first" hypothesis of language origins |journal=Psychonomic Bulletin & Review |volume=24 |issue=1 |pages=163–170 |doi=10.3758/s13423-016-1117-3 |pmc=5325861 |pmid=27439503}}</ref>(humans communicated by gesture first and sound was attached later).

The important question for gestural theories is why there was a shift to vocalization. Various explanations have been proposed:
# Human ancestors started to use more and more tools, meaning that their hands were occupied and could no longer be used for gesturing.<ref>{{Cite book |last=Corballis |first=Michael C. |title=The transition to language |publisher=Oxford University Press |year=2002 |isbn=978-0-19-925066-0 |editor-last=Wray |editor-first=Alison |pages=161–179}}</ref>
# Manual gesturing requires that speakers and listeners be visible to one another. In many situations, they might need to communicate, even without visual contact—for example after nightfall or when foliage obstructs visibility.
# A composite hypothesis holds that early language took the form of part gestural and part vocal [[mimesis]] (imitative 'song-and-dance'), combining modalities because all signals (like those of nonhuman apes and monkeys) still needed to be costly in order to be intrinsically convincing. In that event, each multi-media display would have needed not just to disambiguate an intended meaning but also to inspire confidence in the signal's reliability. The suggestion is that only once community-wide contractual understandings had come into force<ref>{{Cite book |last=Knight |first=Chris |url=http://www.chrisknight.co.uk/wp-content/uploads/2008/01/knight-springer-online-fulltext.pdf |title=The evolution of language: proceedings of the 6th international conference (EVOLANG6), Rome, Italy, 12–15 April 200 |publisher=World Scientific |year=2006 |isbn=9789812566560 |editor-last=Cangelosi |editor-first=Angelo |volume=7 |location=New Jersey |pages=109–128 |chapter=Language co-evolved with the rule of law |journal=Mind & Society |doi=10.1007/s11299-007-0039-1 |editor-last2=Smith |editor-first2=Andrew D. M. |editor-last3=Smith |editor-first3=Kenny |s2cid=143877486}}</ref> could trust in communicative intentions be automatically assumed, at last allowing ''Homo sapiens'' to shift to a more efficient default format. Since vocal distinctive features (sound contrasts) are ideal for this purpose, it was only at this point—when intrinsically persuasive body-language was no longer required to convey each message—that the decisive shift from manual gesture to the current primary reliance on ''spoken'' language occurred.<ref name="Knight2008" /><ref name="Knight1998" /><ref>{{Cite book |last=Knight |first=Chris |title=The Evolutionary emergence of language: social function and the origins of linguistic for |publisher=Cambridge University Press |year=2000 |isbn=978-0-521-78157-2 |editor-last=Chris Knight |pages=99–1119 |chapter=Play as precursor of phonology and syntax |editor-last2=Michael Studdert-Kennedy |editor-last3=James R. Hurford}}</ref>
A comparable hypothesis states that in 'articulate' language, gesture and vocalisation are intrinsically linked, as language evolved from equally intrinsically linked dance and song.<ref name="Vaneechoutte2014" />

Humans still use manual and facial gestures when they speak, especially when people meet who have no language in common.<ref>{{Cite book |last1=Kolb, Bryan |title=Fundamentals of Human Neuropsychology |last2=Ian Q. Whishaw |publisher=Worth Publishers |year=2003 |isbn=978-0-7167-5300-1 |edition=5th |name-list-style=amp}}</ref> There are also a great number of [[sign language]]s still in existence, commonly associated with Deaf communities. These sign languages are equal in complexity, sophistication, and expressive power, to any oral language.<ref>Sandler, Wendy; & Lillo-Martin, Diane. (2006). Sign Language and Linguistic Universals. Cambridge University Press.</ref> The cognitive functions are similar and the parts of the brain used are similar. The main difference is that the "phonemes" are produced on the outside of the body, articulated with hands, body, and facial expression, rather than inside the body articulated with tongue, teeth, lips, and breathing.<ref>{{Cite book |last=Meena |first=Ram Lakhan |title=Current Trends of Applied Linguistics |publisher=K. K. Publications |year=2021 |page=48}}</ref> (Compare the [[motor theory of speech perception]].)

Critics of gestural theory note that it is difficult to name serious reasons why the initial pitch-based vocal communication (which is present in primates) would be abandoned in favor of the much less effective non-vocal, gestural communication.<ref>{{Cite journal |last1=Hewes |first1=Gordon W. |last2=Andrew |first2=R. J. |last3=Carini |first3=Louis |last4=Choe |first4=Hackeny |last5=Gardner |first5=R. Allen |last6=Kortlandt |first6=A. |last7=Krantz |first7=Grover S. |last8=McBride |first8=Glen |last9=Nottebohm |first9=Fernando |last10=Pfeiffer |first10=John |last11=Rumbaugh |first11=Duane G. |last12=Steklis |first12=Horst D. |last13=Raliegh |first13=Michael J. |last14=Stopa |first14=Roman |last15=Suzuki |first15=Akira |year=1973 |title=Primate Communication and the Gestural Origin of Language [and Comments and Reply] |journal=Current Anthropology |volume=14 |issue=1/2 |pages=5–24 |doi=10.1086/201401 |jstor=2741093 |s2cid=146288708 |last16=Washburn |first16=S. L. |last17=Wescott |first17=Roger W.}}</ref> However, [[Michael Corballis]] has pointed out that it is supposed that primate vocal communication (such as alarm calls) cannot be controlled consciously, unlike hand movement, and thus it is not credible as precursor to human language; primate vocalization is rather homologous to and continued in involuntary reflexes (connected with basic human emotions) such as screams or laughter (the fact that these can be faked does not disprove the fact that genuine involuntary responses to fear or surprise exist).<ref name="Kendon2017" /> Also, gesture is not generally less effective, and depending on the situation can even be advantageous, for example in a loud environment or where it is important to be silent, such as on a hunt. Other challenges to the "gesture-first" theory have been presented by researchers in [[psycholinguistics]], including [[David McNeill]].<ref>{{Cite journal |last1=McNeill |first1=David |last2=Bertenthal |first2=Bennett |last3=Cole |first3=Jonathan |last4=Gallagher |first4=Shaun |date=April 2005 |title=Gesture-first, but no gestures? |journal=Behavioral and Brain Sciences |volume=28 |issue=2 |pages=138–139 |doi=10.1017/S0140525X05360031 |s2cid=51753637}}</ref>