Noun
Any language—whether a human language, a programming language, or markup language—that is not a natural language.
(linguistics) A human language that has been consciously devised by an individual or a group, as opposed to having naturally evolved as part of a culture like a natural language.
Synonyms: artificial language, (colloquial) conlang, planned language
Antonyms: (colloquial) natlang, natural language
(linguistics, archaic) Any language used by people, as opposed to less civilized means of communication, such as the socialization between animals.
Source: en.wiktionary.orgAs a matter of fact, a national language which spreads beyond its own confines very quickly loses much of its original richness of content and is in no better case than a constructed language. Edward Sapir
The attitude of independence toward a constructed language which all national speakers must adopt is really a great advantage, because it tends to make man see himself as the master of language instead of its obedient servant. Edward Sapir
The supposed inferiority of a constructed language to a national one on the score of richness of connotation is, of course, no criticism of the idea of a constructed language. Edward Sapir