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The evolutionary emergence of language in the
human species
has been a subject of speculation for several centuries. The topic is
difficult to study because of the lack of direct evidence. Consequently,
scholars wishing to study the origins of language must draw inferences
from other kinds of evidence such as the
fossil record, archaeological evidence, contemporary language diversity, studies of
language acquisition, and comparisons between human
language and systems of communication existing
among animals (particularly
other primates). Many argue that the origins of language probably relate closely to the origins of
modern human behavior, but there is little agreement about the implications and directionality of this connection.
This shortage of
empirical evidence has led many scholars to regard the entire topic as unsuitable for serious study. In 1866, the
Linguistic Society of Paris
banned any existing or future debates on the subject, a prohibition
which remained influential across much of the western world until late
in the twentieth century.
[1] Today, there are various hypotheses about how, why, when, and where language might have emerged.
[2] Despite this, there is scarcely more agreement today than a hundred years ago, when
Charles Darwin's
theory of evolution by
natural selection provoked a rash of armchair speculation on the topic.
[3] Since the early 1990s, however, a number of
linguists,
archaeologists,
psychologists,
anthropologists, and others have attempted to address with new methods what some consider one of the hardest problems in science.
[4]
Approaches
One can sub-divide approaches to the origin of language according to some underlying assumptions:
[5]
- "Continuity theories" build on the idea that language exhibits so
much complexity that one cannot imagine it simply appearing from nothing
in its final form; therefore it must have evolved from earlier
pre-linguistic systems among our primate ancestors.
- "Discontinuity theories" take the opposite approach—that language,
as a unique trait which cannot be compared to anything found among
non-humans, must have appeared fairly suddenly during the course of human evolution.
- Some theories see language mostly as an innate faculty—largely genetically encoded.
- Other theories regard language as a mainly cultural system—learned through social interaction.
Noam Chomsky,
a prominent proponent of discontinuity theory, argues that a single
chance mutation occurred in one individual in the order of 100,000 years
ago, installing the language faculty (a component of the
mind–brain) in "perfect" or "near-perfect" form.
[6] A majority of linguistic scholars as of 2018
hold continuity-based theories, but they vary in how they envision
language development. Among those who see language as mostly innate,
some—notably
Steven Pinker[7]—avoid
speculating about specific precursors in nonhuman primates, stressing
simply that the language faculty must have evolved in the usual gradual
way.
[8] Others in this intellectual camp—notably Ib Ulbæk
[5]—hold that language evolved not from primate communication but from primate cognition, which is significantly more complex.
Those who see language as a socially learned tool of communication, such as
Michael Tomasello,
see it developing from the cognitively controlled aspects of primate
communication, these being mostly gestural as opposed to vocal.
[9][10] Where vocal precursors are concerned, many continuity theorists envisage language evolving from early human capacities for
song.
[11][12][13][14]
[15]
Transcending the continuity-versus-discontinuity divide, some
scholars view the emergence of language as the consequence of some kind
of social transformation
[16]
that, by generating unprecedented levels of public trust, liberated a
genetic potential for linguistic creativity that had previously lain
dormant.
[17][18][19] "Ritual/speech coevolution theory" exemplifies this approach.
[20][21] Scholars in this intellectual camp point to the fact that even
chimpanzees and
bonobos have latent symbolic capacities that they rarely—if ever—use in the wild.
[22]
Objecting to the sudden mutation idea, these authors argue that even if
a chance mutation were to install a language organ in an evolving
bipedal primate, it would be adaptively useless under all known primate
social conditions. A very specific social structure—one capable of
upholding unusually high levels of public accountability and trust—must
have evolved before or concurrently with language to make reliance on
"cheap signals" (words) an
evolutionarily stable strategy.
Because the
emergence of language lies so far back in
human prehistory,
the relevant developments have left no direct historical traces;
neither can comparable processes be observed today. Despite this, the
emergence of new sign languages in modern times—
Nicaraguan Sign Language, for example—may potentially offer insights into the developmental stages and creative processes necessarily involved.
[23] Another approach inspects early human fossils, looking for traces of physical adaptation to language use.
[24][25] In some cases, when the
DNA of extinct humans can be recovered, the presence or absence of genes considered to be language-relevant —
FOXP2, for example—may prove informative.
[26] Another approach, this time
archaeological, involves invoking
symbolic behavior (such as repeated ritual activity) that may leave an archaeological trace—such as mining and modifying ochre pigments for
body-painting—while developing theoretical arguments to justify inferences from
symbolism in general to language in particular.
[27][28][29]
The time range for the evolution of language and/or its anatomical
prerequisites extends, at least in principle, from the phylogenetic
divergence of
Homo (2.3 to 2.4 million years ago) from
Pan (5 to 6 million years ago) to the emergence of full
behavioral modernity some 150,000 – 50,000 years ago. Few dispute that
Australopithecus probably lacked vocal communication significantly more sophisticated than that of
great apes in general,
[30] but scholarly opinions vary as to the developments since the appearance of
Homo some 2.5 million years ago. Some scholars assume the development of primitive language-like systems (
proto-language) as early as
Homo habilis, while others place the development of
symbolic communication only with
Homo erectus (1.8 million years ago) or with
Homo heidelbergensis (0.6 million years ago) and the development of language proper with
Homo sapiens, currently estimated at less than 200,000 years ago.
Using statistical methods to estimate the time required to achieve the current spread and diversity in modern languages,
Johanna Nichols—a linguist at the
University of California, Berkeley—argued in 1998 that vocal languages must have begun diversifying in our species at least 100,000 years ago.
[31] A further study by Q. D. Atkinson
[12]
suggests that successive population bottlenecks occurred as our African
ancestors migrated to other areas, leading to a decrease in genetic and
phenotypic diversity. Atkinson argues that these bottlenecks also
affected culture and language, suggesting that the further away a
particular language is from Africa, the fewer
phonemes
it contains. By way of evidence, Atkinson claims that today's African
languages tend to have relatively large numbers of phonemes, whereas
languages from areas in
Oceania
(the last place to which humans migrated), have relatively few. Relying
heavily on Atkinson's work, a subsequent study has explored the rate at
which phonemes develop naturally, comparing this rate to some of
Africa's oldest languages. The results suggest that language first
evolved around 350,000–150,000 years ago, which is around the time when
modern
Homo sapiens evolved.
[32]
Estimates of this kind are not universally accepted, but jointly
considering genetic, archaeological, palaeontological and much other
evidence indicates that language probably emerged somewhere in
sub-Saharan Africa during the
Middle Stone Age, roughly contemporaneous with the speciation of
Homo sapiens.[33]
Language origin hypotheses
Early speculations
I cannot doubt that language owes its origin to the imitation and
modification, aided by signs and gestures, of various natural sounds,
the voices of other animals, and man's own instinctive cries.
—
Charles Darwin, 1871. The Descent of Man, and Selection in Relation to Sex[34]
In 1861, historical linguist
Max Müller published a list of speculative theories concerning the origins of spoken language:
[35]
- Bow-wow. The bow-wow or cuckoo theory, which Müller attributed to the German philosopher Johann Gottfried Herder, saw early words as imitations of the cries of beasts and birds.
- Pooh-pooh. The pooh-pooh theory saw the first words as emotional interjections and exclamations triggered by pain, pleasure, surprise, etc.
- Ding-dong. Müller suggested what he called the ding-dong theory, which states that all things have a vibrating natural resonance, echoed somehow by man in his earliest words.
- Yo-he-ho. The yo-he-ho theory claims language emerged
from collective rhythmic labor, the attempt to synchronize muscular
effort resulting in sounds such as heave alternating with sounds such as ho.
- Ta-ta. This did not feature in Max Müller's list, having been proposed in 1930 by Sir Richard Paget.[36] According to the ta-ta theory, humans made the earliest words by tongue movements that mimicked manual gestures, rendering them audible.
Most scholars today consider all such theories not so much wrong—they
occasionally offer peripheral insights—as comically naïve and
irrelevant.
[37][38] The problem with these theories is that they are so narrowly mechanistic.
[citation needed] They assume that once our ancestors had stumbled upon the appropriate ingenious
mechanism for linking sounds with meanings, language automatically evolved and changed.
Problems of reliability and deception
From the perspective of modern science, the main obstacle to the
evolution of language-like communication in nature is not a mechanistic
one. Rather, it is the fact that symbols—arbitrary associations of
sounds or other perceptible forms with corresponding meanings—are
unreliable and may well be false.
[39] As the saying goes, "words are cheap".
[40] The problem of reliability was not recognized at all by Darwin, Müller or the other early evolutionary theorists.
Animal vocal signals are, for the most part, intrinsically reliable.
When a cat purrs, the signal constitutes direct evidence of the animal's
contented state. We trust the signal, not because the cat is inclined
to be honest, but because it just cannot fake that sound. Primate vocal
calls may be slightly more manipulable, but they remain reliable for the
same reason—because they are hard to fake.
[41] Primate social intelligence is "
Machiavellian"—self-serving and unconstrained by moral scruples. Monkeys and apes often attempt to
deceive each other, while at the same time remaining constantly on guard against falling victim to deception themselves.
[42][43]
Paradoxically, it is theorized that primates' resistance to deception
is what blocks the evolution of their signalling systems along
language-like lines. Language is ruled out because the best way to guard
against being deceived is to ignore all signals except those that are
instantly verifiable. Words automatically fail this test.
[20]
Words are easy to fake. Should they turn out to be lies, listeners
will adapt by ignoring them in favor of hard-to-fake indices or cues.
For language to work, then, listeners must be confident that those with
whom they are on speaking terms are generally likely to be honest.
[44] A peculiar feature of language is "
displaced reference",
which means reference to topics outside the currently perceptible
situation. This property prevents utterances from being corroborated in
the immediate "here" and "now". For this reason, language presupposes
relatively high levels of mutual trust in order to become established
over time as an
evolutionarily stable strategy.
This stability is born of a longstanding mutual trust and is what
grants language its authority. A theory of the origins of language must
therefore explain why humans could begin trusting cheap signals in ways
that other animals apparently cannot (see
signalling theory).
The 'mother tongues' hypothesis
The "mother tongues" hypothesis was proposed in 2004 as a possible solution to this problem.
[45] W. Tecumseh Fitch suggested that the Darwinian principle of '
kin selection'
[46]—the
convergence of genetic interests between relatives—might be part of the
answer. Fitch suggests that languages were originally 'mother tongues'.
If language evolved initially for communication between mothers and
their own biological offspring, extending later to include adult
relatives as well, the interests of speakers and listeners would have
tended to coincide. Fitch argues that shared genetic interests would
have led to sufficient trust and cooperation for intrinsically
unreliable signals—words—to become accepted as trustworthy and so begin
evolving for the first time.
Critics of this theory point out that kin selection is not unique to humans.
[47]
Other primate mothers also share genes with their progeny, as do all
other animals, so why is it only humans who speak? Furthermore, it is
difficult to believe that early humans restricted linguistic
communication to genetic kin: the incest taboo must have forced men and
women to interact and communicate with more distant relatives. So even
if we accept Fitch's initial premises, the extension of the posited
'mother tongue' networks from close relatives to more distant relatives
remains unexplained.
[47] Fitch argues, however, that the extended period of physical immaturity of human infants and the postnatal
growth of the human brain
give the human-infant relationship a different and more extended period
of intergenerational dependency than that found in any other species.
[45]
Another criticism of Fitch's theory is that language today is not
predominantly used to communicate to kin. Although Fitch's theory can
potentially explain the origin of human language, it cannot explain the
evolution of modern language.
[45]
The 'obligatory reciprocal altruism' hypothesis
Ib Ulbæk
[5] invokes another standard Darwinian principle—'
reciprocal altruism'
[48]—to
explain the unusually high levels of intentional honesty necessary for
language to evolve. 'Reciprocal altruism' can be expressed as the
principle that
if you scratch my back, I'll scratch yours. In linguistic terms, it would mean that
if you speak truthfully to me, I'll speak truthfully to you.
Ordinary Darwinian reciprocal altruism, Ulbæk points out, is a
relationship established between frequently interacting individuals. For
language to prevail across an entire community, however, the necessary
reciprocity would have needed to be enforced universally instead of
being left to individual choice. Ulbæk concludes that for language to
evolve, society as a whole must have been subject to moral regulation.
Critics point out that this theory fails to explain when, how, why or
by whom 'obligatory reciprocal altruism' could possibly have been
enforced.
[21] Various proposals have been offered to remedy this defect.
[21]
A further criticism is that language doesn't work on the basis of
reciprocal altruism anyway. Humans in conversational groups don't
withhold information to all except listeners likely to offer valuable
information in return. On the contrary, they seem to want to
advertise to the world
their access to socially relevant information, broadcasting that
information without expectation of reciprocity to anyone who will
listen.
[49]
The gossip and grooming hypothesis
Gossip, according to
Robin Dunbar in his book
Grooming, Gossip and the Evolution of Language, does for group-living humans what
manual grooming
does for other primates—it allows individuals to service their
relationships and so maintain their alliances on the basis of the
principle:
if you scratch my back, I'll scratch yours. Dunbar
argues that as humans began living in increasingly larger social groups,
the task of manually grooming all one's friends and acquaintances
became so time-consuming as to be unaffordable.
[50] In response to this problem, humans developed 'a cheap and ultra-efficient form of grooming'—
vocal grooming.
To keep allies happy, one now needs only to 'groom' them with low-cost
vocal sounds, servicing multiple allies simultaneously while keeping
both hands free for other tasks. Vocal grooming then evolved gradually
into vocal language—initially in the form of 'gossip'.
[50]
Dunbar's hypothesis seems to be supported by the fact that the
structure of language shows adaptations to the function of narration in
general.
[51]
Critics of this theory point out that the very efficiency of 'vocal
grooming'—the fact that words are so cheap—would have undermined its
capacity to signal commitment of the kind conveyed by time-consuming and
costly manual grooming.
[52]
A further criticism is that the theory does nothing to explain the
crucial transition from vocal grooming—the production of pleasing but
meaningless sounds—to the cognitive complexities of syntactical speech.
Ritual/speech coevolution
The ritual/speech coevolution theory was originally proposed by social anthropologist
Roy Rappaport[17] before being elaborated by anthropologists such as Chris Knight,
[20] Jerome Lewis,
[53] Nick Enfield,
[54] Camilla Power
[44] and Ian Watts.
[29] Cognitive scientist and robotics engineer
Luc Steels[55] is another prominent supporter of this general approach, as is biological anthropologist/neuroscientist
Terrence Deacon.
[56]
These scholars argue that there can be no such thing as a 'theory of
the origins of language'. This is because language is not a separate
adaptation but an internal aspect of something much wider—namely, human
symbolic culture as a whole.
[19]
Attempts to explain language independently of this wider context have
spectacularly failed, say these scientists, because they are addressing a
problem with no solution. Can we imagine a historian attempting to
explain the emergence of credit cards independently of the wider system
of which they are a part? Using a credit card makes sense only if you
have a bank account institutionally recognized within a certain kind of
advanced capitalist society—one where electronic communications
technology and digital computers have already been invented and fraud
can be detected and prevented. In much the same way, language would not
work outside a specific array of social mechanisms and institutions. For
example, it would not work for a nonhuman ape communicating with others
in the wild. Not even the cleverest nonhuman ape could make language
work under such conditions.
Lie and alternative, inherent in language ... pose problems to any
society whose structure is founded on language, which is to say all
human societies. I have therefore argued that if there are to be words
at all it is necessary to establish The Word, and that The Word is established by the invariance of liturgy.
Advocates of this school of thought point out that words are cheap.
As digital hallucinations, they are intrinsically unreliable. Should an
especially clever nonhuman ape, or even a group of articulate nonhuman
apes, try to use words in the wild, they would carry no conviction. The
primate vocalizations that do carry conviction—those they actually
use—are unlike words, in that they are emotionally expressive,
intrinsically meaningful and reliable because they are relatively costly
and hard to fake.
Language consists of digital contrasts whose cost is essentially
zero. As pure social conventions, signals of this kind cannot evolve in a
Darwinian social world — they are a theoretical impossibility.
[39]
Being intrinsically unreliable, language works only if you can build up
a reputation for trustworthiness within a certain kind of
society—namely, one where symbolic cultural facts (sometimes called
'institutional facts') can be established and maintained through
collective social endorsement.
[58] In any hunter-gatherer society, the basic mechanism for establishing trust in symbolic cultural facts is collective
ritual.
[59]
Therefore, the task facing researchers into the origins of language is
more multidisciplinary than is usually supposed. It involves addressing
the evolutionary emergence of human symbolic culture as a whole, with
language an important but subsidiary component.
Critics of the theory include Noam Chomsky, who terms it the
'non-existence' hypothesis—a denial of the very existence of language as
an object of study for natural science.
[60] Chomsky's own theory is that language emerged in an instant and in perfect form,
[61]
prompting his critics in turn to retort that only something that does
not exist—a theoretical construct or convenient scientific fiction—could
possibly emerge in such a miraculous way.
[18] The controversy remains unresolved.
Tool culture resilience and grammar in early Homo
While
it is possible to imitate the making of tools like those made by early
Homo under circumstances of demonstration being possible, research on
primate tool cultures show that non-verbal cultures are vulnerable to
environmental change. In particular, if the environment in which a skill
can be used disappears for a longer period of time than an individual
ape's or early human's lifespan, the skill will be lost if the culture
is imitative and non-verbal. Chimpanzees, macaques and capuchin monkeys
are all known to lose tool techniques under such circumstances.
Researchers on primate culture vulnerability therefore argue that since
early Homo species as far back as Homo habilis retained their tool
cultures despite many climate change cycles at the timescales of
centuries to millennia each, these species had sufficiently developed
language abilities to verbally describe complete procedures, and
therefore grammar and not only two-word "proto-language".
[62][63]
The theory that early Homo species had sufficiently developed brains
for grammar is also supported by researchers who study brain development
in children, noting that grammar is developed while connections across
the brain are still significantly lower than adult level. These
researchers argue that these lowered system requirements for grammatical
language make it plausible that the genus Homo had grammar at
connection levels in the brain that were significantly lower than those
of Homo sapiens and that more recent steps in the evolution of the human
brain were not about language.
[64][65]
Chomsky's single step theory
According to Chomsky's single mutation theory, the emergence of language resembled the formation of a crystal; with
digital infinity as the
seed crystal in a super-saturated primate brain, on the verge of blossoming into the human mind, by physical law, once
evolution added a single small but crucial keystone.
[66][61]
Whilst some suggest it follows from this theory that language appeared
rather suddenly within the history of human evolution, Chomsky, writing
with computational linguist and computer scientist Robert C. Berwick,
suggests it is completely compatible with modern biology. They note
"none of the recent accounts of human language evolution seem to have
completely grasped the shift from conventional Darwinism to its fully
stochastic
modern version—specifically, that there are stochastic effects not only
due to sampling like directionless drift, but also due to directed
stochastic variation in fitness, migration, and heritability—indeed, all
the "forces" that affect individual or gene frequencies. ... All this
can affect evolutionary outcomes—outcomes that as far as we can make out
are not brought out in recent books on the evolution of language, yet
would arise immediately in the case of any new genetic or individual
innovation, precisely the kind of scenario likely to be in play when
talking about language's emergence."
Citing evolutionary geneticist
Svante Pääbo they concur that a substantial difference must have occurred to differentiate
Homo sapiens from
Neanderthals
to "prompt the relentless spread of our species who had never crossed
open water up and out of Africa and then on across the entire planet in
just a few tens of thousands of years. ... What we do not see is any
kind of "gradualism" in new tool technologies or innovations like fire,
shelters, or figurative art." Berwick and Chomsky therefore suggest
language emerged approximately between 200,000 years ago and 60,000
years ago (between the arrival of the first anatomically modern humans
in southern Africa, and the last exodus from Africa, respectively).
"That leaves us with about 130,000 years, or approximately 5,000–6,000
generations of time for evolutionary change. This is not 'overnight in
one generation' as some have (incorrectly) inferred—but neither is it on
the scale of geological eons. It's time enough—within the ballpark for
what Nilsson and Pelger (1994) estimated as the time required for the
full evolution of a
vertebrate eye from a single cell, even without the invocation of any 'evo-devo' effects."
[67]
Gestural theory
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.[68]
Research has 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 oral language.
[69]
Other researchers found that the same left-hemisphere brain regions
were active during sign language as during the use of vocal or written
language.
[70]
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.
[71]
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.
[71]
There is also the fact that, from infancy, gestures both supplement and predict speech.
[72][73]
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 we use despite being able 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,
[74] one of which supports the gestural theory:
- Language developed from the calls of our ancestors.
- Language was derived from gesture.
The first perspective that language evolved from the calls of our
ancestors seems logical because both humans and animals make sounds or
cries. One evolutionary reason to refute this is that, anatomically, the
center that controls calls in monkeys and other animals is located in a
completely different part of the brain than in humans. In monkeys, this
center 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.
[74]
Therefore, we resort to the idea that language was derived from gesture
(we 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:
- Our ancestors started to use more and more tools, meaning that their
hands were occupied and could no longer be used for gesturing.[75]
- 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[76] 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 our current primary reliance on spoken language occurred.[18][20][77]
A comparable hypothesis states that in 'articulate' language, gesture
and vocalisation are intrinsically linked, as language evolved from
equally intrinsically linked dance and song.
[15] Humans still use manual and facial gestures when they speak, especially when people meet who have no language in common.
[78] There are also, of course, a great number of
sign languages still in existence, commonly associated with
deaf communities. These sign languages are equal in complexity, sophistication, and expressive power, to any oral language
[citation needed].
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.
[citation needed] (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.
[citation needed] 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 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).
[citation needed]
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.
[citation needed]
Tool-use associated sound in the evolution of language
Proponents
of the motor theory of language evolution have primarily focused on the
visual domain and communication through observation of movements. The
Tool-use sound hypothesis suggests that the production and perception of sound, also contributed substantially, particularly
incidental sound of locomotion (
ISOL) and
tool-use sound (
TUS). Human bipedalism resulted in rhythmic and more predictable
ISOL.
That may have stimulated the evolution of musical abilities, auditory
working memory, and abilities to produce complex vocalizations, and to
mimic natural sounds.
[80] Since the human brain proficiently extracts information about objects and events from the sounds they produce,
TUS, and mimicry of
TUS,
might have achieved an iconic function. The prevalence of sound
symbolism in many extant languages supports this idea. Self-produced TUS
activates multimodal brain processing (
motor neurons, hearing,
proprioception, touch, vision), and
TUS
stimulates primate audiovisual mirror neurons, which is likely to
stimulate the development of association chains. Tool use and auditory
gestures involve motor-processing of the forelimbs, which is associated
with the evolution of vertebrate vocal communication. The production,
perception, and mimicry of
TUS may have resulted in a limited number of vocalizations or protowords that were associated with tool use.
A new way to communicate about tools, especially when out of sight,
would have had selective advantage. A gradual change in acoustic
properties and/or meaning could have resulted in arbitrariness and an
expanded repertoire of words. Humans have been increasingly exposed to
TUS over millions of years, coinciding with the period during which spoken language evolved.
Mirror neurons and language origins
In humans,
functional MRI studies have reported finding areas homologous to the monkey
mirror neuron system in the
inferior frontal cortex, close to
Broca's area,
one of the language regions of the brain. This has led to suggestions
that human language evolved from a gesture performance/understanding
system implemented in mirror neurons. Mirror neurons have been said to
have the potential to provide a mechanism for action-understanding,
imitation-learning, and the simulation of other people's behavior.
[81] This hypothesis is supported by some
cytoarchitectonic homologies between monkey premotor area F5 and human Broca's area.
[82] Rates of
vocabulary expansion link to the ability of
children to vocally mirror non-words and so to acquire the new word pronunciations. Such
speech repetition occurs automatically, quickly
[83] and separately in the brain to
speech perception.
[84][85] Moreover, such vocal imitation can occur without comprehension such as in
speech shadowing[86] and
echolalia.
[82][87]
Further evidence for this link comes from a recent study in which the
brain activity of two participants was measured using fMRI while they
were gesturing words to each other using hand gestures with a game of
charades—a modality that some have suggested might represent the evolutionary precursor of human language. Analysis of the data using
Granger Causality
revealed that the mirror-neuron system of the observer indeed reflects
the pattern of activity of in the motor system of the sender, supporting
the idea that the motor concept associated with the words is indeed
transmitted from one brain to another using the mirror system.
[88]
Not all linguists agree with the above arguments, however. In
particular, supporters of Noam Chomsky argue against the possibility
that the mirror neuron system can play any role in the hierarchical
recursive structures essential to syntax.
[89]
Putting the baby down theory
According to
Dean Falk's
'putting the baby down' theory, vocal interactions between early
hominid mothers and infants sparked a sequence of events that led,
eventually, to our ancestors' earliest words.
[90]
The basic idea is that evolving human mothers, unlike their
counterparts in other primates, couldn't move around and forage with
their infants clinging onto their backs. Loss of fur in the human case
left infants with no means of clinging on. Frequently, therefore,
mothers had to put their babies down. As a result, these babies needed
to be reassured that they were not being abandoned. Mothers responded by
developing 'motherese'—an infant-directed communicative system
embracing facial expressions, body language, touching, patting,
caressing, laughter, tickling and emotionally expressive contact calls.
The argument is that language somehow developed out of all this.
[90]
In
The Mental and Social Life of Babies, psychologist
Kenneth Kaye
noted that no usable adult language could have evolved without
interactive communication between very young children and adults. "No
symbolic system could have survived from one generation to the next if
it could not have been easily acquired by young children under their
normal conditions of social life."
[91]
Grammaticalisation theory
'
Grammaticalisation'
is a continuous historical process in which free-standing words develop
into grammatical appendages, while these in turn become ever more
specialized and grammatical. An initially 'incorrect' usage, in becoming
accepted, leads to unforeseen consequences, triggering knock-on effects
and extended sequences of change. Paradoxically, grammar evolves
because, in the final analysis, humans care less about grammatical
niceties than about making themselves understood.
[92] If this is how grammar evolves today, according to this school of
thought, we can legitimately infer similar principles at work among our
distant ancestors, when grammar itself was first being established.
[93][94][95]
In order to reconstruct the evolutionary transition from early
language to languages with complex grammars, we need to know which
hypothetical sequences are plausible and which are not. In order to
convey abstract ideas, the first recourse of speakers is to fall back on
immediately recognizable concrete imagery, very often deploying
metaphors rooted in shared bodily experience.
[96]
A familiar example is the use of concrete terms such as 'belly' or
'back' to convey abstract meanings such as 'inside' or 'behind'. Equally
metaphorical is the strategy of representing temporal patterns on the
model of spatial ones. For example, English speakers might say 'It is
going to rain,' modeled on 'I am going to London.' This can be
abbreviated colloquially to 'It's gonna rain.' Even when in a hurry, we
don't say 'I'm gonna London'—the contraction is restricted to the job of
specifying tense. From such examples we can see why grammaticalization
is consistently unidirectional—from concrete to abstract meaning, not
the other way around.
[93]
Grammaticalization theorists picture early language as simple, perhaps consisting only of nouns.
[95]p. 111
Even under that extreme theoretical assumption, however, it is
difficult to imagine what would realistically have prevented people from
using, say, 'spear' as if it were a verb ('Spear that pig!'). People
might have used their nouns as verbs or their verbs as nouns as occasion
demanded. In short, while a noun-only language might seem theoretically
possible, grammaticalization theory indicates that it cannot have
remained fixed in that state for any length of time.
[93][97]
Creativity drives grammatical change.
[97]
This presupposes a certain attitude on the part of listeners. Instead
of punishing deviations from accepted usage, listeners must prioritize
imaginative mind-reading. Imaginative creativity—emitting a leopard
alarm when no leopard was present, for example—is not the kind of
behavior which, say,
vervet monkeys would appreciate or reward.
[98] Creativity and reliability are incompatible demands; for
'Machiavellian' primates as for animals generally, the overriding
pressure is to demonstrate reliability.
[99] If humans escape these constraints, it is because in our case, listeners are primarily interested in mental states.
To focus on mental states is to accept fictions—inhabitants of the
imagination—as potentially informative and interesting. Take the use of
metaphor. A metaphor is, literally, a false statement.
[100] Think of Romeo's declaration, 'Juliet is the sun!' Juliet is a woman,
not a ball of plasma in the sky, but human listeners are not (or not
usually) pedants insistent on point-by-point factual accuracy. They want
to know what the speaker has in mind. Grammaticalization is essentially
based on metaphor. To outlaw its use would be to stop grammar from
evolving and, by the same token, to exclude all possibility of
expressing abstract thought.
[96][101]
A criticism of all this is that while grammaticalization theory might
explain language change today, it does not satisfactorily address the
really difficult challenge—explaining the initial transition from
primate-style communication to language as we know it. Rather, the
theory assumes that language already exists. As Bernd Heine and Tania
Kuteva acknowledge: "Grammaticalization requires a linguistic system
that is used regularly and frequently within a community of speakers and
is passed on from one group of speakers to another".
[95] Outside modern humans, such conditions do not prevail.
Evolution-Progression Model
Human
language is used for self-expression; however, expression displays
different stages. The consciousness of self and feelings represents the
stage immediately prior to the external, phonetic expression of feelings
in the form of sound, i.e., language. Intelligent animals such as
dolphins, Eurasian magpies, and chimpanzees live in communities, wherein
they assign themselves roles for group survival and show emotions such
as sympathy.
[102] When such animals view their reflection (mirror test), they recognize themselves and exhibit self-consciousness.
[103]
Notably, humans evolved in a quite different environment than that of
these animals. The human environment accommodated the development of
interaction, self-expression, and tool-making as survival became easier
with the advancement of tools, shelters, and fire-making.
[104]
The increasing brain size allowed advanced provisioning and tools and
the technological advances during the Palaeolithic era that built upon
the previous evolutionary innovations of bipedalism and hand versatility
allowed the development of human language.
[citation needed]
Self-domesticated ape theory
According to a study investigating the song differences between
white-rumped munias and its domesticated counterpart (
Bengalese finch),
the wild munias use a highly stereotyped song sequence, whereas the
domesticated ones sing a highly unconstrained song. In wild finches,
song syntax is subject to female preference—
sexual selection—and
remains relatively fixed. However, in the Bengalese finch, natural
selection is replaced by breeding, in this case for colorful plumage,
and thus, decoupled from selective pressures, stereotyped song syntax is
allowed to drift. It is replaced, supposedly within 1000 generations,
by a variable and learned sequence. Wild finches, moreover, are thought
incapable of learning song sequences from other finches.
[105] In the field of
bird vocalization,
brains capable of producing only an innate song have very simple neural
pathways: the primary forebrain motor center, called the robust nucleus
of
arcopallium,
connects to midbrain vocal outputs, which in turn project to brainstem
motor nuclei. By contrast, in brains capable of learning songs, the
arcopallium receives input from numerous additional forebrain regions,
including those involved in learning and social experience. Control over
song generation has become less constrained, more distributed, and more
flexible.
[106]
One way to think about human evolution is that we are
self-domesticated apes. Just as domestication relaxed selection for
stereotypic songs in the finches—mate choice was supplanted by choices
made by the aesthetic sensibilities of bird breeders and their
customers—so might our cultural domestication have relaxed selection on
many of our primate behavioral traits, allowing old pathways to
degenerate and reconfigure. Given the highly indeterminate way that
mammalian brains develop—they basically construct themselves "bottom
up", with one set of neuronal interactions setting the stage for the
next round of interactions—degraded pathways would tend to seek out and
find new opportunities for synaptic hookups. Such inherited
de-differentiations of brain pathways might have contributed to the
functional complexity that characterizes human language. And, as
exemplified by the finches, such de-differentiations can occur in very
rapid time-frames.
[107]
Speech and language for communication
A distinction can be drawn between
speech and
language.
Language is not necessarily spoken: it might alternatively be written
or signed. Speech is among a number of different methods of encoding and
transmitting linguistic information, albeit arguably the most natural
one.
[108]
Some scholars view language as an initially cognitive development,
its 'externalisation' to serve communicative purposes occurring later in
human evolution. According to one such school of thought, the key
feature distinguishing human language is
recursion,
[109] (in this context, the iterative embedding of phrases within phrases). Other scholars—notably
Daniel Everett—deny that recursion is universal, citing certain languages (e.g.
Pirahã) which allegedly lack this feature.
[110]
The ability to ask questions is considered by some to distinguish language from non-human systems of communication.
[111] Some captive primates (notably
bonobos and
chimpanzees),
having learned to use rudimentary signing to communicate with their
human trainers, proved able to respond correctly to complex questions
and requests. Yet they failed to ask even the simplest questions
themselves.
[citation needed] Conversely, human children are able to ask their first questions (using only question
intonation)
at the babbling period of their development, long before they start
using syntactic structures. Although babies from different cultures
acquire native languages from their social environment, all languages of
the world without exception—tonal, non-tonal, intonational and
accented—use similar rising "question intonation" for
yes–no questions.
[112][113] This fact is a strong evidence of the universality of
question intonation.
In general, according to some authors, sentence intonation/pitch is
pivotal in spoken grammar and is the basic information used by children
to learn the grammar of whatever language.
[15]
Cognitive development and language
One of the intriguing abilities that language users have is that of high-level
reference (or
deixis),
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 non-linguistic 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[109]
Theory of mind
Simon Baron-Cohen (1999) argues that theory of mind must have preceded language use, based on evidence
[clarification needed]
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.
[citation needed] 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.
[citation needed]
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.
[citation needed]
Number representation
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.
[109]
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 with each number
requiring a similar amount of training time; yet, after learning the
meaning of 1, 2 and 3 (and sometimes 4), children easily comprehend the
value of greater integers by using a successor function (i.e. 2 is 1
greater than 1, 3 is 1 greater than 2, 4 is 1 greater than 3; once 4 is
reached it seems most children have an
"a-ha!" moment and understand that the value of any integer
n
is 1 greater than the previous integer). Put simply, other primates
learn the meaning of numbers one by one, similar to their approach to
other referential symbols, while children first learn an arbitrary list
of symbols (1, 2, 3, 4...) and then later learn their precise meanings.
[114]
These results can be seen as evidence for the application of the
"open-ended generative property" of language in human numeral cognition.
[109]
Linguistic structures
Lexical-phonological principle
Hockett (1966) details a list of features regarded as essential to describing human language.
[115] 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.
[citation needed]
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 coexist within the same
species. Bird-song, singing nonhuman apes, and the songs of whales all
display phonological syntax, combining units of sound into larger
structures apparently devoid of enhanced or novel meaning. Certain other
primate species 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.
[citation needed]
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.
[116]
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.
[116]
Evolutionary timeline
Primate communication
Field primatologists can give us useful insights into
great ape communication in the wild.
[30]
An important finding is that nonhuman primates, including the other
great apes, produce calls that are graded, as opposed to categorically
differentiated, with listeners striving to evaluate subtle gradations in
signalers' emotional and bodily states. Nonhuman apes seemingly find it
extremely difficult to produce vocalizations in the absence of the
corresponding emotional states.
[41] In captivity, nonhuman apes have been taught rudimentary forms of sign language or have been persuaded to use
lexigrams—symbols that do not graphically resemble the corresponding words—on computer keyboards. Some nonhuman apes, such as
Kanzi, have been able to learn and use hundreds of lexigrams.
[117][118]
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.
[119]
In the wild, the communication of
vervet monkeys has been the most extensively studied.
[116]
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".
[120]
Each call triggers a different defensive strategy in the monkeys who
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.
[121][122]
Similarly, researchers have demonstrated that chimpanzees (in
captivity) use different "words" in reference to different foods. They
recorded vocalizations that chimps made in reference, for example, to
grapes, and then other chimps pointed at pictures of grapes when they
heard the recorded sound.
[123][124]
Ardipithecus ramidus
A study published in
Homo: Journal of Comparative Human Biology in 2017 claims that
A. ramidus,
a hominin dated at approximately 4.5Ma, shows the first evidence of an
anatomical shift in the hominin lineage suggestive of increased vocal
capability.
[125] This study compared the skull of
A. ramidus with twenty nine chimpanzee skulls of different ages and found that in numerous features
A. ramidus
clustered with the infant and juvenile measures as opposed to the adult
measures. Significantly, such affinity with the shape dimensions of
infant and juvenile chimpanzee skull architecture was argued may have
resulted in greater vocal capability. This assertion was based on the
notion that the chimpanzee vocal tract ratios that prevent speech are a
result of growth factors associated with puberty—growth factors absent
in
A. ramidus ontogeny.
A. ramidus was also found to have a
degree of cervical lordosis more conducive to vocal modulation when
compared with chimpanzees as well as cranial base architecture
suggestive of increased vocal capability.
What was significant in this study was the observation that the
changes in skull architecture that correlate with reduced aggression are
the same changes necessary for the evolution of early hominin vocal
ability. In integrating data on anatomical correlates of primate mating
and social systems with studies of skull and vocal tract architecture
that facilitate speech production, the authors argue that
paleoanthropologists to date have failed to grasp the important relationship between early hominin social evolution and language capacity.
In the paleoanthropological literature, these changes in early
hominin skull morphology [reduced facial prognathism and lack of canine
armoury] have to date been analysed in terms of a shift in mating and
social behaviour, with little consideration given to vocally mediated
sociality. Similarly, in the literature on language evolution there is a
distinct lacuna regarding links between craniofacial correlates of
social and mating systems and vocal ability. These are surprising
oversights given that pro-sociality and vocal capability require
identical alterations to the common ancestral skull and skeletal
configuration. We therefore propose a model which integrates data on
whole organism morphogenesis with evidence for a potential early
emergence of hominin socio-vocal adaptations. Consequently, we suggest
vocal capability may have evolved much earlier than has been
traditionally proposed. Instead of emerging in the genus
Homo, we
suggest the palaeoecological context of late Miocene and early Pliocene
forests and woodlands facilitated the evolution of hominin socio-vocal
capability. We also propose that paedomorphic morphogenesis of the skull
via the process of self-domestication enabled increased levels of
pro-social behaviour, as well as increased capacity for socially
synchronous vocalisation to evolve at the base of the hominin clade.
[125]
While the skull of
A. ramidus, according to the authors, lacks
the anatomical impediments to speech evident in chimpanzees, it is
unclear what the vocal capabilities of this early hominin were. While
they suggest
A. ramidus—based on similar vocal tract ratios—may
have had vocal capabilities equivalent to a modern human infant or very
young child, they concede this is obviously a debatable and speculative
hypothesis. However, they do claim that changes in skull architecture
through processes of social selection were a necessary prerequisite for
language evolution. As they write:
We propose that as a result of paedomorphic morphogenesis of the cranial base and craniofacial morphology Ar. ramidus
would have not been limited in terms of the mechanical components of
speech production as chimpanzees and bonobos are. It is possible that Ar. ramidus
had vocal capability approximating that of chimpanzees and bonobos,
with its idiosyncratic skull morphology not resulting in any significant
advances in speech capability. In this sense the anatomical features
analysed in this essay would have been exapted in later more voluble
species of hominin. However, given the selective advantages of
pro-social vocal synchrony, we suggest the species would have developed
significantly more complex vocal abilities than chimpanzees and bonobos.[125]
Early Homo
Regarding articulation, there is considerable speculation about the language capabilities of early
Homo (2.5 to 0.8 million years ago). Anatomically, some scholars believe features of
bipedalism, which developed in
australopithecines
around 3.5 million years ago, would have brought changes to the 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.
[citation needed] 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.
[126][127] It was earlier proposed that differences between
Homo sapiens and Neanderthal vocal tracts could be seen in fossils, but the finding that the Neanderthal
hyoid bone (see below) was identical to that found in
Homo sapiens
has weakened these theories. Still another view considers the lowering
of the larynx as irrelevant to the development of speech.
[128]
Archaic Homo sapiens
Steven Mithen proposed the term
Hmmmmm for the pre-linguistic system of communication used by archaic
Homo. beginning with
Homo ergaster and reaching the highest sophistication in the
Middle Pleistocene with
Homo heidelbergensis and
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 facial),
musical, and
mimetic.
[129]
Homo heidelbergensis
Homo heidelbergensis was a close relative (most probably a migratory descendant) of
Homo ergaster. Some researchers believe this species to be the first hominin to make
controlled vocalizations, possibly mimicking animal vocalizations,
[129] and that as
Homo heidelbergensis developed more sophisticated culture, proceeded from this point and possibly developed an early form of symbolic language.
Homo neanderthalensis
The discovery in 1989 of the (Neanderthal) Kebara 2 hyoid bone
suggests that Neanderthals may have been anatomically capable of
producing sounds similar to modern humans.
[130][131] The
hypoglossal nerve,
which passes through the hypoglossal canal, controls the movements of
the tongue, which may have enabled voicing for size exaggeration (see
size exaggeration hypothesis below) or may reflect speech abilities.
[25][132][133][134][135][136]
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 hominins 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 aesthetic 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.
[137][138] The issue of the Neanderthal's level of cultural and technological sophistication remains a controversial one.
Based on computer simulations used to evaluate that evolution of
language that resulted in showing three stages in the evolution of
syntax, Neanderthals are thought to have been in stage 2, showing they
had something more evolved than proto-language but not quite as complex
as the language of modern humans.
[139]
Homo sapiens
Anatomically modern humans begin to
appear in the fossil record in Ethiopia some 200,000 years ago.
[140]
Although there is still much debate as to whether behavioural modernity
emerged in Africa at around the same time, a growing number of
archaeologists nowadays invoke the southern African Middle Stone Age use
of red ochre pigments—for example at
Blombos Cave—as evidence that modern anatomy and behaviour co-evolved.
[141]
These archaeologists argue strongly that if modern humans at this early
stage were using red ochre pigments for ritual and symbolic purposes,
they probably had symbolic language as well.
[142]
According to the
recent African origins hypothesis, from around 60,000 – 50,000 years ago
[143]
a group of humans left Africa and began migrating to occupy the rest of
the world, carrying language and symbolic culture with them.
[144]
The descended larynx
The
larynx or
voice box is an organ in the neck housing the
vocal folds, which are responsible for
phonation. In humans, the larynx is
descended. Our species is not unique in this respect: goats, dogs, pigs and tamarins lower the larynx temporarily, to emit loud calls.
[145]
Several deer species have a permanently lowered larynx, which may be
lowered still further by males during their roaring displays.
[146] Lions, jaguars, cheetahs and domestic cats also do this.
[147]
However, laryngeal descent in nonhumans (according to Philip Lieberman)
is not accompanied by descent of the hyoid; hence the tongue remains
horizontal in the oral cavity, preventing it from acting as a pharyngeal
articulator.
[148]
| Larynx |
|
|
|
Despite all this, scholars remain divided as to how "special" the
human vocal tract really is. It has been shown that the larynx does
descend to some extent during development in chimpanzees, followed by
hyoidal descent.
[149]
As against this, Philip Lieberman points out that only humans have
evolved permanent and substantial laryngeal descent in association with
hyoidal descent, resulting in a curved tongue and two-tube vocal tract
with 1:1 proportions. Uniquely in the human case, simple contact between
the epiglottis and velum is no longer possible, disrupting the normal
mammalian separation of the respiratory and digestive tracts during
swallowing. Since this entails substantial costs—increasing the risk of
choking while swallowing food—we are forced to ask what benefits might
have outweighed those costs. The obvious benefit—so it is claimed—must
have been speech. But this idea has been vigorously contested. One
objection is that humans are in fact
not seriously at risk of choking on food: medical statistics indicate that accidents of this kind are extremely rare.
[150] Another objection is that in the view of most scholars, speech as we
know it emerged relatively late in human evolution, roughly
contemporaneously with the emergence of
Homo sapiens.[32]
A development as complex as the reconfiguration of the human vocal
tract would have required much more time, implying an early date of
origin. This discrepancy in timescales undermines the idea that human
vocal flexibility was
initially driven by selection pressures for speech, thus not excluding that it was selected for e.g. improved singing ability.
The size exaggeration hypothesis
To lower the larynx is to increase the length of the vocal tract, in turn lowering
formant
frequencies so that the voice sounds "deeper"—giving an impression of
greater size. John Ohala argues that the function of the lowered larynx
in humans, especially males, is probably to enhance threat displays
rather than speech itself.
[151]
Ohala points out that if the lowered larynx were an adaptation for
speech, we would expect adult human males to be better adapted in this
respect than adult females, whose larynx is considerably less low. In
fact, females invariably outperform males in verbal tests
[citation needed],
falsifying this whole line of reasoning. W. Tecumseh Fitch likewise
argues that this was the original selective advantage of laryngeal
lowering in our species. Although (according to Fitch) the initial
lowering of the larynx in humans had nothing to do with speech, the
increased range of possible formant patterns was subsequently co-opted
for speech. Size exaggeration remains the sole function of the extreme
laryngeal descent observed in male deer. Consistent with the size
exaggeration hypothesis, a second descent of the larynx occurs at
puberty in humans, although only in males. In response to the objection
that the larynx is descended in human females, Fitch suggests that
mothers vocalising to protect their infants would also have benefited
from this ability.
[152]
Phonemic diversity
In 2011, Quentin Atkinson published a survey of
phonemes from 500 different languages as well as
language families
and compared their phonemic diversity by region, number of speakers and
distance from Africa. The survey revealed that African languages had
the largest number of phonemes, and
Oceania
and South America had the smallest number. After allowing for the
number of speakers, the phonemic diversity was compared to over 2000
possible origin locations. Atkinson's "best fit" model is that language
originated in central and southern Africa between 80,000 and 160,000
years ago. This predates the hypothesized
southern coastal peopling
of Arabia, India, southeast Asia, and Australia. It would also mean
that the origin of language occurred at the same time as the emergence
of symbolic culture.
[153]
History
In religion and mythology
The search for the origin of language has a long history rooted in
mythology. Most mythologies do not credit humans with the invention of language but speak 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.
Vāc is the Hindu goddess of speech, or "speech personified". As
Brahman's "sacred utterance", she has a cosmological role as the "Mother of the
Vedas". The
Aztecs' story maintains that only a man,
Coxcox, and a woman,
Xochiquetzal,
survived a flood, having floated on a piece of bark. They found
themselves on land and begat many children who were at first born unable
to speak, but subsequently, upon the arrival of a
dove, were endowed with language, although each one was given a different speech such that they could not understand one another.
[154]
In the Old Testament, the Book of Genesis (11) says that God prevented the
Tower of Babel
from being completed through a miracle that made its construction
workers start speaking different languages. After this, they migrated to
other regions, grouped together according to which of the newly created
languages they spoke, explaining the origins of languages and nations
outside of the fertile crescent.
Historical experiments
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 (
Histories 2.2). He relates that Pharaoh Psammetichus (probably
Psammetichus I,
7th century BC) had two children raised by a shepherd, with the
instructions that no one should speak to them, but that the shepherd
should feed and care for them while listening to determine their first
words. When one of the children cried "bekos" with outstretched arms the
shepherd concluded that the word was
Phrygian,
because that was the sound of 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.
[155]
Both the medieval monarch
Frederick II and
Akbar are said to have tried similar experiments; the children involved in these experiments did not speak. The current situation of
deaf people also points into this direction.
History of research
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 origin 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.
[citation needed]
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.
[citation needed]
The "origin of language" as a subject in its own right emerged from 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.
[citation needed]
