Language deathIn linguistics, language death occurs when a language loses its last native speaker. By extension, language extinction is when the language is no longer known, including by second-language speakers, when it becomes known as an extinct language. A related term is linguicide, the death of a language from natural or political causes, and, rarely, glottophagy, the absorption or replacement of a minor language by a major language.
LanguageLanguage is a structured system of communication that consists of grammar and vocabulary. It is the primary means by which humans convey meaning, both in spoken and written forms, and may also be conveyed through sign languages. The vast majority of human languages have developed writing systems that allow for the recording and preservation of the sounds or signs of language. Human language is characterized by its cultural and historical diversity, with significant variations observed between cultures and across time.
Extinct languageAn extinct language is a language that no longer has any speakers, especially if the language has no living descendants. In contrast, a dead language is one that is no longer the native language of any community, even if it is still in use, like Latin. A dormant language is a dead language that still serves as a symbol of ethnic identity to a particular group. These languages are often undergoing a process of revitalisation. Languages that currently have living native speakers are sometimes called modern languages to contrast them with dead languages, especially in educational contexts.
Mathematical proofA mathematical proof is a deductive argument for a mathematical statement, showing that the stated assumptions logically guarantee the conclusion. The argument may use other previously established statements, such as theorems; but every proof can, in principle, be constructed using only certain basic or original assumptions known as axioms, along with the accepted rules of inference. Proofs are examples of exhaustive deductive reasoning which establish logical certainty, to be distinguished from empirical arguments or non-exhaustive inductive reasoning which establish "reasonable expectation".
Second languageA second language (L2) is a language spoken in addition to one's first language (L1). A second language may be a neighbouring language, another language of the speaker's home country, or a foreign language. A speaker's dominant language, which is the language a speaker uses most or is most comfortable with, is not necessarily the speaker's first language. For example, the Canadian census defines first language for its purposes as "the first language learned in childhood and still spoken", recognizing that for some, the earliest language may be lost, a process known as language attrition.
Language revitalizationLanguage revitalization, also referred to as language revival or reversing language shift, is an attempt to halt or reverse the decline of a language or to revive an extinct one. Those involved can include linguists, cultural or community groups, or governments. Some argue for a distinction between language revival (the resurrection of an extinct language with no existing native speakers) and language revitalization (the rescue of a "dying" language).
Proof (truth)A proof is sufficient evidence or a sufficient argument for the truth of a proposition. The concept applies in a variety of disciplines, with both the nature of the evidence or justification and the criteria for sufficiency being area-dependent. In the area of oral and written communication such as conversation, dialog, rhetoric, etc., a proof is a persuasive perlocutionary speech act, which demonstrates the truth of a proposition.
Proof theoryProof theory is a major branch of mathematical logic and theoretical computer science within which proofs are treated as formal mathematical objects, facilitating their analysis by mathematical techniques. Proofs are typically presented as inductively-defined data structures such as lists, boxed lists, or trees, which are constructed according to the axioms and rules of inference of a given logical system. Consequently, proof theory is syntactic in nature, in contrast to model theory, which is semantic in nature.
Constructed languageA constructed language (shortened to a conlang) is a language whose phonology, grammar, and vocabulary, instead of having developed naturally, are consciously devised for some purpose, which may include being devised for a work of fiction. A constructed language may also be referred to as an artificial, planned or invented language, or (in some cases) a fictional language. Planned languages (or engineered languages/engelangs) are languages that have been purposefully designed; they are the result of deliberate, controlling intervention and are thus of a form of language planning.
Indigenous languageAn indigenous language, or autochthonous language, is a language that is native to a region and spoken by indigenous peoples. This language is from a linguistically distinct community that originated in the area. Indigenous languages are not necessarily national languages but they can be; for example, Aymara is an official language of Bolivia. Also, national languages are not necessarily indigenous to the country.
