Language

Language is the human capacity for acquiring and using complex systems of communication, and a language is any specific example of such a system. The scientific study of language is called linguistics. It is impossible to know precisely how many languages there are in the world, and the number depends on a partly arbitrary distinction between languages and dialects. However, estimates vary between around 6,000 and 7,000 languages in number. Natural languages are spoken or signed, but any language can be encoded into secondary media using auditory, visual or tactile stimuli, for example in graphic writing, braille, or whistling. This is because human language is modality-independent. When used as a general concept, "language" may refer to the cognitive ability to learn and use systems of complex communication, or to describe the set of rules that makes up these systems, or the set of utterances that can be produced from those rules.

Human language is unique among the lifeforms of Earth because its complex structure affords a much wider range of possible expressions and uses than any known system of animal communication, all of which are generally closed systems, with limited functions and mostly genetically rather than socially transmitted. In contrast to non-human communication forms, human language has the properties of productivity, recursivity, and displacement. Human language is also the only system to rely mostly on social convention and learning. Language is thought to have originated when early hominins first started cooperating, gradually changing their primate communication systems as they acquired the ability to form a theory of other minds and shared intentionality.

This development is thought to have coincided with an increase in brain volume, and many linguists see the structures of language as having evolved to serve specific communicative functions. Language is processed in many different locations in the human brain, but especially in Broca’s and Wernicke’s areas. Humans acquire language through social interaction in early childhood, and children generally speak fluently when they are around three years old. The use of language is deeply entrenched in human culture. Therefore, in addition to its strictly communicative uses, language also has many social and cultural uses, such as signifying group identity, social stratification, as well as for social grooming and entertainment.

All languages rely on the process of semiosis to relate signs with particular meanings. Oral and sign languages contain a phonological system that governs how symbols are used to form sequences known as words or morphemes, and a syntactic system that governs how words and morphemes are combined to form phrases and utterances. Languages evolve and diversify over time, and the history of their evolution can be reconstructed by comparing modern languages to determine which traits their ancestral languages must have had for the later stages to have occurred. A group of languages that descend from a common ancestor is known as a language family. The languages that are most spoken in the world today belong to the Indo-European family, which includes languages such as English, Spanish, Portuguese, Russian and Hindi; the Sino-Tibetan languages, which include Mandarin Chinese, Cantonese and many others; Semitic languages, which include Arabic, Amharic and Hebrew; and the Bantu languages, which include Swahili, Zulu, Shona and hundreds of other languages spoken throughout Africa. The general consensus is that between 50 to 90% of languages spoken today will probably have become extinct by the year 2100.