Types of languages
Natlang A language which came into existence completely naturally without any designer or creator. Natlang is short for "natural language".Conlang A language which was intentionally designed for a purpose. Conlang is short for "constructed language".
A priori A prior languages are constructed languages in which the words are completely artificial and aren't borrowed from any existing language. A prior languages are mostly used in a fictional setting like in Game of Thrones or Lord of the Rings.
A posteriori A posteriori languages are constructed languages in which the words are borrowed from an already existing language. Generally, these are used as auxlangs.