IETF language tag

An IETF language tag is an abbreviated language code (for example, en for English, pt-BR for Brazilian Portuguese, or nan-Hant-TW for Min Nan Chinese as spoken in Taiwan using traditional Han characters) defined by the Internet Engineering Task Force (IETF) in the BCP 47 document series, which is currently composed of normative RFC 5646 (referencing the related RFC 5645) and RFC 4647, along with the normative content of the IANA Language Subtag Registry. Components of language tags are drawn from ISO 639, ISO 15924, ISO 3166-1, and UN M.49.

These language tags are used in a number of modern computing standards, including those from the IETF related to the Internet protocols such as HTTP, those from the World Wide Web Consortium such as HTML,XML and PNG, and those from other private standardization bodies such as SGML or Unicode (in some of its standard annexes), or from national or regional standard bodies like ANSI or ECMA (for example in some of their standards related to computing languages, or to bibliographic references and documents classification used in institutional libraries).

Language

Language is the ability to acquire and use complex systems of communication, particularly the human ability to do so, and a language is any specific example of such a system. The scientific study of language is called linguistics.

Questions concerning the philosophy of language, such as whether words can represent experience, have been debated since Gorgias and Plato in Ancient Greece. Thinkers such as Rousseau have argued that language originated from emotions while others like Kant have held that it originated from rational and logical thought. 20th-century philosophers such as Wittgenstein argued that philosophy is really the study of language. Major figures in linguistics include Ferdinand de Saussure, Noam Chomsky and William C. Stokoe.

Estimates of the number of languages in the world vary between 5,000 and 7,000. However, any precise estimate depends on a partly arbitrary distinction between languages and dialects. 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. Depending on philosophical perspectives regarding the definition of language and meaning, 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. All languages rely on the process of semiosis to relate signs to 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.