Conlangs are classified into types and subtypes based mainly on why they are created. The three basic types are engelangs (engineered languages), auxlangs (auxiliary languages), and artlangs (artistic languages).
Whatever your reason for making a language, it's good to always remember why you started it in the first place.
Engelangs, sometimes called englangs, are conlangs designed to meet objective criteria, rather than subjective goals like "elegance" or "ease of use". For example, one might design an engelang so that the arrangement of sounds in a word classifies its meaning; or so that its grammatical structure imitates formal logic; or so that its expressions conform to a certain ideology or point of view (say, Taoism, or feminism). Subjective goals are always around — motivating the choice of objective criteria, and filling in gaps in the language design that the objective criteria don't address. As long as the technical criteria take precedence when deciding features of the language design, it's an engelang.
Be aware (and beware) that the names for this type of conlang and its subtypes vary a bit across the conlanging community. What we're calling engelangs here, some conlangers call loglangs (a term we're using just for the ones that implement formal logic); and some other conlangers call them philosophical languages (a term we're using for a subtype of engelangs distinct from loglangs).
Loglangs are conlangs built around the structure of formal logic. They are usually designed to investigate how the human mind would work when using a language with that structure. Logical languages tend to have few or no irregularities and be similar in style to computer programming or markup languages. They advocate a logical and consistent architectural structure of utterances. Lojban, a language created to test the Sapir–Whorf Hypothesis (the idea that language shapes the operation of the mind), is considered archetypal of the genre. Others are like Ithkuil, a language created by John Quijada: Ithkuil exists as an exercise in how human languages could function. These often overlap with philosophical languages.
Some examples of loglangs:
- — developed in the mid-twentieth century, originally as a tool with which to test the Sapir–Whorf Hypothesis.
- — a community-driven offshoot of Loglan. Its development is ongoing.
- Ceqli — originally inspired by Loglan, then took a turn toward the naturalistic.
- — a knowledge representation language, for an attempt to create artificial intelligence through vast accumulation of knowledge.
- — intended to express thoughts precisely and densely.
Philosophical languages are conlangs constructed to meet some philosophical goal. This goal can be to explore how the mind works by altering the fundamental structure of the language (which is the aim of some loglangs, such as Ithkuil), or it can be to see if language is even possible when certain elements are changed. In general, philosophical languages are experimental.
In some of them, for example, all the words for manmade objects (artifacts) will typically begin with the same letter, t for instance, all the words for pieces of furniture will begin with to-, the word for "chair" will be tod, words for different types of chairs will begin with tod-, organisms will begin with v, plant species will begin with ve- while animals begin with vu-, all vertebrates will begin with vuz-, mammals with vuzu- and rodents with vuzum-.
A common criticism of languages that use such a word categorization system is that the words that are most similar in meaning and topic, and will therefore most need to be distinguished from each other, will sound too alike, and become too confusable to learn, even though the goal of these languages is usually to make memorization easier. In a few of these languages a single phoneme or very short (two-letter) syllable will indicate an element of meaning, such as "light/vision", "female", or "many".
Some examples of philosophical languages:
- — seventeenth century classification language. It has been described as paving the way for Roget's Thesaurus.
- — 1960s. Each sound has a meaning, and the meanings of words are built up from the meanings of the sounds.
- — early twentieth century classification language. One of its supporters was Melvil Dewey, creator of the Dewey Decimal System.
- Ygyde — twenty-first century. Two-letter morphemes carry meaning, and longer words are built up as compounds.
- — twenty-first century. Designed to facilitate Taoist thinking. Very few words with no inflections and uncomplicated meanings, and very simple grammar.
Auxlangs are designed to help ease communication between two or more linguistically diverse communities. They use simple phonology and grammar to try to ensure that they are easy to learn. Their grammars are made in such a way that they can express the widest range of meanings possible. There are many Auxlangs, and some of them were among the first constructed languages ever made.
Some examples of auxlangs:
- — probably the most widely known auxlang. It includes words from languages of several Indo-European branches and has a highly developed system of word derivation.
- — the most successful auxlang prior to Esperanto. Its vocabulary is derived from Germanic roots.
- — derived from Esperanto, separating in an event called the schism (or even the Great Schism) from which resentments have not entirely faded a century later. Ido uses a Romance-derived vocabulary.
- Latin without inflections. — based on
- — based on modern West European languages.
- — based on the musical scale. It can be sung and played.
Many auxlangs borrow their vocabulary entirely from the Indo-European languages — often from a mix of Romance and Germanic languages, but most often entirely from Romance languages. As a result, the vocabulary and general method of reaching the goal of universality sound a lot alike from auxlang to auxlang. These auxlangs are often called "Euroclones". More recent auxlangs that take their vocabulary from more diverse sources and use non-Indo-European grammar include Vorlin, Ceqli, Ilomi, Dunia, and SASXSEK.
Artlangs are created for a wide range of reasons: fleshing out works of fiction, fun, experimentation, or even historical study (colloquially called "if-langs"). Most people who create artlangs do so simply because they enjoy it. The artlangs best known today are probably Klingon, from the Star Trek movies, designed by professional linguist Marc Okrand, and the many Elvish languages, most notably Quenya and Sindarin, in Tolkien's Middle-earth.
The most familiar and general subset of artlangs are fictional languages. These are spoken by the inhabitants of the fictional worlds of a book, movie, television show, video game, comic, or toy, such as Middle-earth, the Star Trek universe, or the game Myst. These worlds in which they are spoken are called conworlds, inhabited by fictional concultures. The conworld influences what words the language will have for flora and fauna, articles of clothing, foods, objects of technology (such as bricks, cannons, or telephones), sports, music genres, ethnic groups, religious concepts, and place names.
The culture will also have an influence on some things like verb tenses (how your people view the future and the past, or whether time should even be grammatically indicated at all any more than place should), pronouns (whether the speakers need fine enough shades of "we" to distinguish the concept of "you and I" from "he and I", or whether they have different levels of formality for "you"), and how kinship terms are split up (some languages have different words for older and younger brothers, others do not distinguish "brother" from "sister", and some have different words for the sister of a sister and the sister of a brother). Tolkien started out inventing languages for his amusement and then retroengineered a fictional universe to have a world in which these languages would be spoken.
Since the Internet became popular, many people have now become able to put up information on their conlangs and associated conworlds on their sites, and these have become famous. Verdurian, the language of Mark Rosenfelder's Verduria on the planet of Almea, is often invoked as a symbolic representative of these Net-based fictional languages.
Some examples of fictional languages:
- — created for the Star Trek franchise by linguist Marc Okrand; meant to have a harsh sound, but be pronounceable by actors, and to reflect a suitably bellicose worldview.
- — created for the movie Avatar by professor Paul Frommer; meant to fit the film concept, and be pronounceable by actors, but not sound like any particular human language.
- — described in George Orwell's novel 1984; supposed to prevent dissident thoughts by not allowing them to be expressed.
- and — the most prominent of J.R.R. Tolkien's Elvish languages; designed to Tolkien's personal taste. He created Middle-earth as background for the languages.
- — created by Mark Rosenfelder for a Dungeons & Dragons world; borrows from various European languages, but doesn't closely resemble any of them.
Altlangs are also known as What if? languages or if-langs. They speculate on an alternate history and try to reconstruct how a family of natural languages would have evolved if things had been different. What if King Harold had won the Battle of Hastings? What if the Polynesians had settled in Central America during the time of Meso-American Empires? What if Alexander the Great had not been able to conquer Egypt? What if Greek civilization went on to thrive without a Roman Empire, leaving Greek and not Latin to develop several modern descendants? The language that would have evolved is then traced step by step in its evolution, to reach its final form.
The revered grandfather of this genre is Andrew Smith's Brithenig, which attempts to determine what Romance languages would have evolved into had the Romans displaced the Celtic people in Great Britain. The vocabulary of Latin is altered through the same evolution that befell Welsh from the evolution of the Celtic languages through the present day. An altlang will typically base itself on the core vocabulary of one language and the phonology of another. An altlang will ideally have meticulous understanding and admirable imagination as to world history, sturdy knowledge of linguistics, and ingenious improvising when it becomes necessary to "toss it up".
Some examples of altlangs:
- — might have evolved if Latin had displaced the native Celtic language in Great Britain.
- — might have evolved if the Romans had conquered Poland.
Personal languages are languages that are created by and belong just to the inventor, for just the inventor to see, or perhaps to show off. A personal language is created for the ultimate purpose of creating a language. There is no conworld it is associated with, no people whom the creator actually expects to speak it, no product that will be manufactured in its language. A personal language is considered by many to be artlanging in its purest form, although a personal language may well have no artistic intention behind it. A personal language may be invented to create a beautiful language or for self-expression. It may be invented to give out a tribute to a language or language family the creator really likes, attempting to capture the flavor of the original as much as possible, or it may be created just for the fun that there is in creating a language.
Personal languages are often created as practices in linguistics; a conlanger learning about ergativity might write out the grammar of an ergative conlang in order to understand how ergative languages work. Some exist to test outlandish phonologies or orthographic systems, or have hundreds of noun cases or tens of millions of possible verb forms. Many are invented simply because people love constructing languages! The creators of personal languages often share their languages and update their progress over the Internet, and many habitually scrap an old conlang project that hasn't gotten beyond a lexicon of 50 words and start a new one. These personal languages tend to have short lifespans, but others are developed for years on end as their creators try to become truly fluent in them, perhaps using them for diaries and other writings.
Some artlangs are micronational languages — like fictional languages, but their creators make them real. They declare territory, issue official flags and currency, and recruit citizens, then have the citizens learn the language. These are the languages of micronations, sometimes created for entertainment, but often breakaway nations that are created for political purposes, declaring themselves to exist alongside UN-recognized nations (such as Sealand, the Conch Republic, or Atlantium). The members of these micronations meet up and speak the language they have learned when they are participating in these meets. The language and its creation belong to all the citizens of these micronations. They determine the direction of its evolution, invent new grammatical constructions when they discover it is necessary, and coin new words as they speak.
Some examples of micronational languages:
Other ways of classifying conlangs
The three broad kinds of goals we've described — technical features, cross-cultural communication, and art — aren't mutually exclusive. What if your goal is to see whether a certain technical goal can be successfully combined with your personal aesthetics? Is that an engelang or an artlang? Liva is a conlang with just that sort of goals, and its author has suggested that conlangs should be placed on the interior of a triangle, with the three pure types of conlangs at its corners (see here).
Even if a conlang has a single, pure primary goal, there are enough details in any conlang that the primary goal probably doesn't cover all of them. Auxlangs have some artistry in their making — it's been argued that artistic merit is part of why Esperanto has succeeded so much better than its competitors. Engelangs may have some artistry in them, too; and artlangs often have some technical aspirations lurking under the surface.
A particular class of mixed-goal conlangs with its own name is the fauxlangs, short for fictional auxlangs. These are supposed auxlangs created by characters in a fictional setting, often in an alternative history. Examples include
- Rex May's Texperanto — created by L.L. Zamenhof, the creator of Esperanto, in an alternative history where he emigrated to the Republic of Texas.
- Ray Brown's το άνευ κλίσι Ελληνικό ("Greek without inflections") — the analog, in an alternative history where Alexander the Great conquered Rome, of Giuseppe Peano's 1903 auxlang .
A relex is a conlang generated from a pre-existing language by replacing the forms of the words, while leaving most of the rest of the original language unchanged — especially,
- the exact meanings of the words from the original language, and/or
- the grammar of the original language.
With both of these unchanged, the conlang is a sort of word-replacement code for the original language. By extension, relex is sometimes used as a broad criticism of any conlang seen as too closely copying another language.
The largest class of relexes are (by reputation, at least) artlangs whose authors failed to notice that they were copying most of the look and feel of their native language. Not all relexes are artlangs, though, and not all are unintentional. Auxlangs Speedwords and Glosa have both been criticized as relexes of English. The loglang started as a deliberate relex of , since which their grammars and vocabularies have gradually diverged as both languages underwent further development (see here).
The conlanging term relex is a shortening of the term relexification, borrowed and adapted from linguistics proper. The linguistic term has a narrower meaning: in linguistic, a pre-existing language keeps its grammar but replaces its vocabulary from another pre-existing language. The language from which the vocabulary is taken is called the lexifier.
A priori and a posteriori
Particular features of a conlang can be a posteriori — meaning borrowed from natural languages, rather than invented — or a priori, meaning invented rather than borrowed from natural languages. These terms are most often used to describe the forms of words, as with thewords toki, from the English word talk, and pona, from Latin bona (good). An entire conlang may also be described as a priori/posteriori if most of its grammar and vocabulary are of that type. A conlang described as a posteriori usually borrows from several, or even many, different natlangs; relexes are not normally called a posteriori.
Classification-based vocabulary is an a priori strategy that has been used in a number of engelangs (e.g.,) and some auxlangs (e.g., ). Most auxlangs make extensive use of a posteriori vocabulary.
A diachronic conlang is equipped with an internal, i.e., fictional, linguistic history. Since the internal history is fictional, all diachronic conlangs are artlangs; but most subtypes of artlangs include both diachronic and non-diachronic (synchronic) languages.
Tolkien's Elvish languages are the most famous example of diachronic conlanging, with an entire family of languages descended from a common ancestor,. Many artlangs, though by no means all, have at least some suggestions of internal history about them, even if no parent language has been fully worked out.
Altlangs are diachronic, by definition.
Kitchen sink languages
A kitchen sink conlang is one that has way too many exotic features, all at once for no apparent reason — "everything including the kitchen sink" in an uncoordinated mishmash. Unlike relex, kitchen sink has no neutral technical sense; it's always a strong term of opprobrium.
Kitchen sink languages are at the opposite end of a spectrum from relexes: where too little tinkering can produce a relex (that lacks interest), too much tinkering can produce a kitchen sink language (that lacks plausibility). It has been suggested that a conlanger's second conlang is often a kitchen sink language; but even experienced conlangers, tempted by the lure of exotic features, can sometimes fall into the trap of kitchen-sink-ism.
Caution should also be exercised, though, in applying the term kitchen sink to a conlang — not only because it's such a strong term, but because just having many unusual features doesn't necessarily make it a kitchen sink language (which is why the term is so strong). For proper use of the term, the many unusual features should be unjustified; in principle, at least, it's possible for many unusual features to occur in a smoothly coherent design, so that they all feel quite natural in context. The catch is that — as David Peterson remarked when awarding the 2007 Smiley Award to , a highly respected conlang with several unusual features — there is a double standard at work between natlangs and conlangs: any bizarre features of a natlang are natural by definition, but the same features in a conlang would have to persuade on their own merits. His case in point is , a natlang with no way of expressing time; no way of counting; a culture with no storytelling, oral history, or art; it can be spoken, whistled, hummed, or drummed; and it has different phonologies for men and women. If it were a conlang instead of a natlang, its creator would have a hard time passing it off as naturalistic.