Euroclone - An international auxiliary language derived primarily from European stock. Most have primarily Romance vocabulary and/or use Classical roots (Greek and Latin) and/or some English roots. (Usually, but not always, used pejoratively.)
fictional language - A model language intended to be used by characters in a fictional setting, typically for added verisimilitude and regardless of whether the fictional setting has been highly commercialized or barely outlined, whether the medium is a movie, a novel, a short story, a historical sketch, a game or something else.
fictional diachronic language - A model language with an elaborate fictional history, typically tracing its evolution from an ancestor language or language family (which may be a natural language or model language).
fictional naming language - A fictional language developed primarily to have a way to name the people, places and things of an imaginary world and therefore typically consisting of just a hundred or so words of vocabulary, with little or no grammatical details.
international auxiliary language- A model language intended as a lingua franca that will be easy for citizens of different countries to learn. An auxiliary language can be intended for worldwide use or for use within a region (typically Europe).
logical language - A model language intended to remove as much ambiguity (typically syntactical ambiguity) as possible from human communication.
model language - An invented language intended primarily for humans or fictional sentient beings to converse with others of their kind.
personal language - A model language intended for personal amusement or edification.
philosophical language - A model language intended as international auxiliary language, but with a schematic vocabulary, with the initial letters of the word indicating its place in a semantic hierarchy; in other words, the vocabulary is a priori rather than borrowing actual terms from other languages.
stealth language - A model language intended primarily for secret communications with others or oneself (through a journal).
superset language - A superset of a natural language, such as a slang for English. A superset language involves the creation of new vocabulary, but typically little grammatical change.