The Conlangers' Jargon File

This file lists a number of words and phrases commonly used by conlangers (what do you expect from people who make up entire languages for fun or profit, than making up words?), as encountered in fora such as the CONLANG mailing list or the Zompist Bulletin Board. Mainstream linguistic terminology, which is also frequently used (not always correctly) by conlangers, is not included here.

AFMCL: As for my conlang.
altlang: A fictlang spoken in an alternative timeline. Famous example: Brithenig.
ANADEW: A natlang already did except worse. The observation that most "exotic" features conlangers may come up with are actually found in at least one of the 6000-odd natlangs of our planet.
artlang: An artistic language, i.e. a language designed with an artistic purpose. Many artlangs are fictlangs.
auxlang: An international auxiliary language.
bogolang: A term coined by Geoff A. Eddy for a diachronic conlang obtained by applying the sound changes of one language to another language. Famous example: Brithenig, which applies the sound changes of Welsh to Latin (more or less). Bogolangs are often altlangs.
briefscript: A conlang that is very concise in written form (term coined by Raymond A. Brown). See also speedtalk.
conlang: Constructed language. Also used as a verb: to conlang = to make conlangs.
conlanger: Someone who makes conlangs. Similarly: artlanger, auxlanger, engelanger etc.
conscript: A constructed writing system.
conworld: A constructed (fictional) world.
cookie cutter conlang: A conlang in which everything is unnaturally regular and symmetric, from the phoneme inventory to the inflectional paradigms. A symptom commonly found in nooblangs.
diachronic conlang: A conlang (usually a fictlang) with a simulated linguistic history; usually created by applying a Grand Master Plan to a protolang.
engelang: An engineered language, i.e. a language designed to fulfill specified objectively testable design criteria. Often used more laxly to mean a non-naturalistic conlang.
etabnannery: Excessive apparent irregularity which, unlike maggelity which is really irregular, only hides a very complicated regularity, especially in spelling. (After a conlang named "Etabnanni" by Tristan McLeay.)
euroclone: A conlang (usually an auxlang) that structurally resembles a western European language.
exolang: A fictlang spoken by extraterrestrial beings.
fauxlang: A fictional auxlang, i.e. a language used as an auxlang in a fictional world.
fictlang: A fictional language, i.e. a language spoken in a fictional world.
frankenlang: A conlang pieced together from parts of many other languages that poorly play together (named after Frankenstein's Monster). See also kitchen sink conlang.
freaklang: A conlang with bizarre, exotic features, such as one without vowels.
Grand Master Plan (GMP): A chronologically ordered list of sound changes for a diachronic conlang.
jankoed: "To get jankoed" = to get asked by Janko Gorenc, a guy from Slovenia who collects number words from languages, for number words from one's conlangs.
kitchen sink conlang: An excessively complicated conlang (one which has "everything including the kitchen sink").
loglan: A loglang that is based on the design principles set out by J. C. Brown for his Loglan project.
loglang: A logical language, i.e. one based on formal logic.
lostlang: A fictlang that is not set in a specific conworld, but represents an extinct language or one spoken by a tiny community in our world. (The term is derived from the League of Lost Languages, a collaborative project that provides a common framework for such languages.)
maggelity: Excessive irregularity, especially in spelling. (After a conlang named "Maggel" by Christophe Grandsire which had a baroque irregular orthography.) Compare etabnannery.
monster raving loony (MRL): A nickname for an unusual morphosyntactic alignment wherein subject and object of a transitive clause are marked with the same case, but intransitive subjects with a different case.
natlang: A natural language, as opposed to a conlang.
naturalistic: Resembling a natlang. This expression is used among auxlangers and artlangers with somewhat different meanings, as most "naturalistic" auxlangs are still too schematic to qualify as "naturalistic" as understood by artlangers. Many naturalistic artlangs are diachronic; this is generally considered the best way of coming up with a truly naturalistic language.
nooblang, n00blang: A linguistically naïve conlang made by a novice conlanger (a newbie).
oligosynthetic: An oligosynthetic language is one that builds its vocabulary from a small (at most a few hundered), closed set of lexical roots. No oligosynthetic natlang is known so far, but several oligosynthetic engelangs have been made. See also speedtalk.
pielang: A diachronic conlang developed from Proto-Indo-European (PIE).
protolang: A language (may be a natlang, conlang or reconlang) used to evolve a diachronic conlang from.
reconlang: A reconstructed language, such as Proto-Indo-European. (Sceptics claim that such reconstructed languages are untruthful enough to consider them outright conlangs.)
romlang: Romance language, especially Romance conlang. Romlangs are popular altlangs but frequently considered overdone.
shotgun phonology: A phoneme inventory that looks as if it has been selected by firing a shotgun at an IPA chart. Famous example: Klingon. The opposite of a cookie cutter phonology.
speedtalk: An extremely concise engelang wherein the number of phonemes per morpheme approaches one. (From the story Gulf by Robert A. Heinlein.) A speedtalk is always oligosynthetic. See also briefscript.
translation relay: Perhaps the most sophisticated form of the telephone game ever invented. In a translation relay, each player translates a text written in a conlang of the previous player into his own conlang. Each player only sees the previous player's version of the text, with glossary and grammar notes, and does not know the original version of the text. In a translation relay, translation errors tend to sum up and the meaning of the text drift away from the original version, which makes part of the fun.
YAEPT: Yet another English pronunciation thread. A very common kind of off-topic thread on the CONLANG mailing list, usually erupting when someone describes the sounds of his conlang in terms of sounds of English - which vary quite much between local varieties, especially the vowels. There is a family of similar expressions, such as YAEGT (yet another English grammar thread) or YASPT (yet another Swedish pronunciation thread).