A language is a dynamic set of visual, auditory, or tactile symbols of communication and the elements used to manipulate them. Language can also refer to the use of such systems as a general phenomenon. Language is considered to be an exclusively human mode of communication; although other animals make use of quite sophisticated communicative systems, none of these are known to make use of all of the properties that linguists use to define language.
In Western Philosophy, language has long been closely associated with reason, which is also a uniquely human way of using symbols. In Ancient Greek philosophical terminology, the same word, logos, was used as a term for both language or speech and reason, and the philosopher Thomas Hobbes used the English word "speech" so that it similarly could refer to reason, as will be discussed below. More commonly though, the English word "language", derived ultimately from lingua, Latin for tongue, typically refers only to expressions of reason which can be understood by other people, most obviously by speaking.
Another property of language is that its symbols are arbitrary. Any concept or grammatical rule can be mapped onto a symbol. Most languages make use of sound, but the combinations of sounds used do not have any inherent meaning – they are merely an agreed-upon convention to represent a certain thing by users of that language. For instance, there is nothing about the Spanish word nada itself that forces Spanish speakers to convey the idea of "nothing". Another set of sounds (for example, the English word nothing) could equally be used to represent the same concept, but all Spanish speakers have acquired or learned to correlate this meaning for this particular sound pattern. For Slovenian, Croatian, Serbian or Bosnian speakers on the other hand, nada means something else; it means "hope".
This arbitrariness does not, however, apply to words with an onomatopoetic dimension (i.e. words that to some extent simulate the sound of the token referred to). For example, the bird cuckoo's name was indeed not given arbitrarily.
The subject is of such interest to philosophy because language is such an essential characteristic of humans. In Classical Greek Philosophy such questions were connected to the subject of the Natures of things, in this case "Human Nature". Therefore already in Aristotle we see language being mentioned in discussions of natural propensities of humans to be political and to dwell in city state types of communities, pair-bonding, poetical and so on.
Hobbes followed by John Locke and others claimed that language is an extension of the "speech" which humans have with themselves, which in a sense takes the classical view that reason is one of the most primary characteristics in humans. Others have argued the opposite - that reason developed out of the need for more complex communication. Rousseau, despite writing before the publication of Darwin's Theory of Evolution, shockingly claimed that there had once been humans who had no language or reason and who developed language first, rather than reason.
Since Darwin the subject has come to be treated more often than not by scientists rather than philosophers. For example neurologist Terrence Deacon, has argued that reason and language "co-evolved". Merlin Donald sees language as a later development building up what he refers to as mimetic culture, emphasizing that this co-evolution depended upon the interactions of many individuals. He writes that:
A shared communicative culture, with sharing of mental representations to some degree, must have come first, before language, creating a social environment in which language would have been useful and adaptive.
The specific causes of the natural selection that led to language are however still the subject of much speculation, but a common theme which goes right back to Aristotle is that many theories propose that the gains to be had from language and/or reason were probably mainly in the area of increasingly sophisticated social structures.
Linguistics is the scientific study of language, encompassing a number of sub-fields. At the core of theoretical linguistics are the study of language structure (grammar) and the study of meaning (semantics). The first of these encompasses morphology (the formation and composition of words), syntax (the rules that determine how words combine into phrases and sentences) and phonology (the study of sound systems and abstract sound units). Phonetics is a related branch of linguistics concerned with the actual properties of speech sounds (phones), non-speech sounds, and how they are produced and perceived.
Theoretical linguistics is mostly concerned with developing models of linguistic knowledge. The fields that are generally considered as the core of theoretical linguistics are syntax, phonology, morphology, and semantics. Applied linguistics attempts to put linguistic theories into practice through areas like translation, stylistics, literary criticism and theory, discourse analysis, speech therapy, speech pathology and foreign language teaching.
Later in the West, the success of science, mathematics, and other formal systems in the 20th century led many to attempt a formalization of the study of language as a "semantic code". This resulted in the academic discipline of linguistics, the founding of which is attributed to Ferdinand de Saussure. In the 20th century, substantial contributions to the understanding of language came from Ferdinand de Saussure, Hjelmslev, Émile Benveniste and Roman Jakobson, which are characterized as being highly systematic.
Human languages are usually referred to as natural languages, and the science of studying them falls under the purview of linguistics. A common progression for natural languages is that they are considered to be first spoken, then written, and then an understanding and explanation of their grammar is attempted.
Languages live, die, move from place to place, and change with time. Any language that ceases to change or develop is categorized as a dead language. Conversely, any language that is in a continuous state of change is known as a living language or modern language.
Making a principled distinction between one language and another is usually impossible. For instance, there are a few dialects of German similar to some dialects of Dutch. The transition between languages within the same language family is sometimes gradual (see dialect continuum).
Some like to make parallels with biology, where it is not possible to make a well-defined distinction between one species and the next. In either case, the ultimate difficulty may stem from the interactions between languages and populations. (See Dialect or August Schleicher for a longer discussion.)
The concepts of Ausbausprache, Abstandsprache and Dachsprache are used to make finer distinctions about the degrees of difference between languages or dialects.
Some individuals and groups have constructed their own artificial languages, for practical, experimental, personal, or ideological reasons. International auxiliary languages are generally constructed languages that strive to be easier to learn than natural languages; other constructed languages strive to be more logical ("loglangs") than natural languages; a prominent example of this is Lojban.
Some writers, such as J. R. R. Tolkien, have created fantasy languages, for literary, artistic or personal reasons. The fantasy language of the Klingon race has in recent years been developed by fans of the Star Trek series, including a vocabulary and grammar.
Constructed languages are not necessarily restricted to the properties shared by natural languages.
This part of ISO 639 also includes identifiers that denote constructed (or artificial) languages. In order to qualify for inclusion the language must have a literature and it must be designed for the purpose of human communication. Specifically excluded are reconstructed languages and computer programming languages.
Some languages, most constructed, are meant specifically for communication between people of different nationalities or language groups as an easy-to-learn second language. Several of these languages have been constructed by individuals or groups. Natural, pre-existing languages may also be used in this way - their developers merely catalogued and standardized their vocabulary and identified their grammatical rules. These languages are called naturalistic. One such language, Latino Sine Flexione, is a simplified form of Latin. Two others, Occidental and Novial, were drawn from several Western languages.
To date, the most successful auxiliary language is Esperanto, invented by Polish ophthalmologist Zamenhof. It has a relatively large community roughly estimated at about 2 million speakers worldwide, with a large body of literature, songs, and is the only known constructed language to have native speakers, such as the Hungarian-born American businessman George Soros. Other auxiliary languages with a relatively large number of speakers and literature are Interlingua and Ido.
Controlled natural languages are subsets of natural languages whose grammars and dictionaries have been restricted in order to reduce or eliminate both ambiguity and complexity. The purpose behind the development and implementation of a controlled natural language typically is to aid non-native speakers of a natural language in understanding it, or to ease computer processing of a natural language. An example of a widely used controlled natural language is Simplified English, which was originally developed for aerospace industry maintenance manuals.
Mathematics and computer science use artificial entities called formal languages (including programming languages and markup languages, and some that are more theoretical in nature). These often take the form of character strings, produced by a combination of formal grammar and semantics of arbitrary complexity.
A programming language is an extreme case of a formal language that can be used to control the behavior of a machine, particularly a computer, to perform specific tasks. Programming languages are defined using syntactic and semantic rules, to determine structure and meaning respectively.
Programming languages are used to facilitate communication about the task of organizing and manipulating information, and to express algorithms precisely. Some authors restrict the term "programming language" to those languages that can express all possible algorithms; sometimes the term "computer language" is used for artificial languages that are more limited.
The term "animal languages" is often used for non-human languages. Linguists do not consider these to be "language", but describe them as animal communication, because the interaction between animals in such communication is fundamentally different in its underlying principles from human language. Nevertheless, some scholars have tried to disprove this mainstream premise through experiments on training chimpanzees to talk. Karl von Frisch received the Nobel Prize in 1973 for his proof of the language and dialects of the bees.
In several publicized instances, non-human animals have been taught to understand certain features of human language. Chimpanzees, gorillas, and orangutans have been taught hand signs based on American Sign Language. The African Grey Parrot, which possesses the ability to mimic human speech with a high degree of accuracy, is suspected of having sufficient intelligence to comprehend some of the speech it mimics. Most species of parrot, despite expert mimicry, are believed to have no linguistic comprehension at all.