Language Language is a structured system of communication. The structure of a language is its grammar and the free components are its vocabulary. Languages are the primary means by which humans communicate, and may be conveyed through a variety of met ...

has a long evolutionary history and is closely related to the

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...

, but what makes the

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

brain uniquely adapted to language is unclear. The regions of the brain that are involved in language in humans have similar analogues in apes and monkeys, and yet they do not use language. There may also be a

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

tic component: mutations in the

FOXP2 Forkhead box protein P2 (FOXP2) is a protein that, in humans, is encoded by the ''FOXP2'' gene. FOXP2 is a member of the forkhead box family of transcription factors, proteins that regulate gene expression by binding to DNA. It is expressed in ...

gene prevent humans from constructing complete sentences.

Neurobiological adaptations for language

Broca's and Wernicke's areas

These regions are where language is located in the brain – everything from

speech Speech is a human vocal communication using language. Each language uses Phonetics, phonetic combinations of vowel and consonant sounds that form the sound of its words (that is, all English words sound different from all French words, even if ...

reading Reading is the process of taking in the sense or meaning of Letter (alphabet), letters, symbols, etc., especially by Visual perception, sight or Somatosensory system, touch. For educators and researchers, reading is a multifaceted process invo ...

and

writing Writing is a medium of human communication which involves the representation of a language through a system of physically Epigraphy, inscribed, Printing press, mechanically transferred, or Word processor, digitally represented Symbols (semiot ...

. Language itself is based on symbols used to represent concepts in the world, and this system appears to be housed in these areas. The language regions in human brains highly resemble similar regions in other primates, even though humans are the only species that use language. The brain structures of chimpanzees are very similar to those of humans. Both contain Broca's and Wernicke's homologues that are involved in communication. Broca's area is largely used for planning and producing vocalizations in both chimpanzees and humans. Wernicke's area appears to be where linguistic representations and symbols are mapped to specific concepts. This functionality is present in both chimpanzees and humans; the chimpanzee Wernicke's area is much more similar to its human counterpart than is the Broca's area, suggesting that Wernicke's is more evolutionary ancient than Broca's.

Motor neurons

In order to speak, the breathing system must be voluntarily repurposed to produce vocal sounds, which allows the breathing mechanisms to be temporarily deactivated in favor of

song A song is a musical composition intended to be performed by the human voice. This is often done at distinct and fixed pitches (melodies) using patterns of sound and silence. Songs contain various forms, such as those including the repetitio ...

or speech production. The human

vocal tract The vocal tract is the cavity in human bodies and in animals where the sound produced at the sound source (larynx in mammals; syrinx (biology), syrinx in birds) is filtered. In birds it consists of the Vertebrate trachea, trachea, the Syrinx (bio ...

has evolved to be more suited to speaking, with a lower

larynx The larynx (), commonly called the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal inlet is about ...

, 90° turn in the windpipe, and large, round tongue.

Motor neurons A motor neuron (or motoneuron or efferent neuron) is a neuron whose cell body is located in the motor cortex, brainstem or the spinal cord, and whose axon (fiber) projects to the spinal cord or outside of the spinal cord to directly or indirectly ...

in birds and humans bypass the unconscious systems in the brainstem to give direct control of the larynx to the brain.

Theories of language origin

Gestural origin

The earliest language was strictly vocal; reading and writing came later. New research suggests that the combination of

gestures A gesture is a form of non-verbal communication or non-vocal communication in which visible bodily actions communicate particular messages, either in place of, or in conjunction with, speech. Gestures include movement of the hands, face, or ot ...

and vocalizations may have led to the development of more complicated language in protohumans. Chimpanzees that produce attention-getting sounds show activation in areas of the brain that are highly similar to Broca's area in humans. Even hand and mouth movements with no vocalizations cause very similar activation patterns in the Broca's area of both humans and monkeys. When monkeys view other monkeys gesturing,

mirror neurons A mirror neuron is a neuron that fires both when an animal acts and when the animal observes the same action performed by another. Thus, the neuron "mirrors" the behavior of the other, as though the observer were itself acting. Such neurons hav ...

in the Broca's homologue activate. Groups of mirror neurons are specialized to respond only to one kind of viewed action, and it is currently believed that these may be an evolutionary origin to the neurons that are adapted for speech processing and production.

Universal grammar

The language bioprogram hypothesis proposes that humans have an innate,

cognitive Cognition refers to "the mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought, ...

grammatical In linguistics, grammaticality is determined by the conformity to language usage as derived by the grammar of a particular variety (linguistics), speech variety. The notion of grammaticality rose alongside the theory of generative grammar, the go ...

structure allowing them to develop and understand language. According to this theory, this system is embedded in human genetics and underpins the basic grammar of all languages. Some evidence suggests that at least some of our linguistic capacities may be genetically controlled. Mutations in the

gene prevent people from combining words and phrases into sentences. However, these genes are present in the heart, lungs, and brain, and their role is not entirely clear. It is possible that the human capacity for grammar evolved from non-semantic behavior like singing. Birds have the ability to produce, process, and learn complex vocalizations, but the units of a birdsong, when removed from the larger meaning and context of the birdsong as a whole, have no inherent meaning. Early hominids may have evolved capacities for similar, non-semantic purposes, that were later modified for symbolic language.

References

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External references

Evolution of language Evolutionary neuroscience Human evolution Paleolithic Causes of events Unsolved problems in linguistics