A constructed or artificial language known colloquially or informally as a conlang is a language whose phonology, grammar, and/or vocabulary have been consciously devised by an individual or group, instead of having evolved naturally. There are many possible reasons to create a constructed language: to ease human communication (see international auxiliary language and code); to bring fiction or an associated constructed world to life; linguistic experimentation; celebration of one's aesthetic tastes in language; and language games.
The synonym planned language is sometimes used to refer to international auxiliary languages and other languages intended for actual use in human communication. Some prefer it to the more common term "artificial", as that term may have pejorative connotations in some languages. For example, few speakers of Interlingua consider their language artificial, since they assert that it has no invented content. While this is not true of Esperanto and Ido, some speakers of these languages also avoid the term "artificial language" because they deny that there is anything "unnatural" about the use of their language in human communication. (In Esperanto itself, the equivalent of English "artificial" does not have the same pejorative connotation, having more connection with the concept of "art".) Some philosophers such as François Rabelais have argued that all human languages are conventional or artificial.
Calling languages "planned" also addresses a difficulty with the term "constructed language": a few languages are loosely grouped under this heading as a result of shared history and uses but are not, by their proponents, themselves viewed as constructed. Interlingua's vocabulary is taken from a small set of natural languages with much less phonological modification than in Esperanto or Ido, and its grammar is based closely on these source languages, even including a certain degree of irregularity; its proponents prefer to describe its vocabulary and grammar as standardized rather than invented.
Similarly, Latino sine Flexione (LsF) is a simplification of Latin from which the inflections have been removed. As with Interlingua, some prefer to describe this process as "planning" rather than "constructing" the language. Both LsF and Interlingua are considered major auxiliary languages, although only Interlingua is widely spoken today.
Outside the Esperanto community, the term language planning refers to prescriptive measures taken regarding a natural language. In this regard, even "natural languages" may be artificial in some respects. In the case of prescriptive grammars, where wholly artificial rules exist, the line is difficult to draw. The term "glossopoeia," coined by J. R. R. Tolkien, is also used to refer to language construction, particularly construction of artistic languages; Sarah L. Higley uses this term in her discussion of artistic constructed languages in Hildegard of Bingen's Unknown Language (2007).
In turn, a posteriori languages are divided into schematic languages, in which a natural or partly natural vocabulary is altered to fit pre-established rules, and naturalistic languages, in which a natural vocabulary retains its normal sound and appearance. While Esperanto is generally considered schematic, Interlingua is viewed as naturalistic. Ido is presented either as a schematic language or as a compromise between the two types.
Further, fictional and experimental languages can be naturalistic in that they are meant to sound natural, have realistic amounts of irregularity, and, if derived a posteriori from a real-world natural language (such as Vulgar Latin or Proto Indo-European) or from a fictional protolanguage, they try to imitate natural processes of phonological, lexical and grammatical change. In contrast with Interlingua, these languages are not usually intended for easy learning or communication; and most artlangers would not consider Interlingua to be naturalistic in the sense in which this term is used in artlang criticism. Thus, a naturalistic fictional language tends to be more difficult and complex. While Interlingua has simpler grammar, syntax, and orthography than its source languages (though more complex and irregular than Esperanto or Ido), naturalistic fictional languages typically mimic behaviors of natural languages like irregular verbs and nouns and complicated phonological processes.
In terms of purpose, most constructed languages can broadly be divided into:
The boundaries between these categories are by no means clear. A constructed language could easily fall into more than one of the above categories. A logical language created for aesthetic reasons would also be classifiable as an artistic language, which might be created by someone with philosophical motives intending for said conlang to be used as an auxiliary language. There are no rules, either inherent in the process of language construction or externally imposed, that would limit a constructed language to fitting only one of the above categories.
A constructed language can have native speakers if young children learn it from parents who speak it fluently. According to Ethnologue, there are "200–2000 who speak Esperanto as a first language" (most famously George Soros). A member of the Klingon Language Institute, d'Armond Speers, attempted to raise his son as a native (bilingual with English) Klingon speaker.
As soon as a constructed language has a community of fluent speakers, especially if it has numerous native speakers, it begins to evolve and hence loses its constructed status. For example, Modern Hebrew was modeled on Biblical Hebrew rather than engineered from scratch, and has undergone considerable changes since the state of Israel was founded in 1948 (Hetzron 1990:693). Esperanto as a living spoken language has evolved significantly from the prescriptive blueprint published in 1887, so that modern editions of the Fundamenta Krestomatio, a 1903 collection of early texts in the language, require many footnotes on the syntactic and lexical differences between early and modern Esperanto.
Proponents of constructed languages often have many reasons for using them. The famous but disputed Sapir-Whorf hypothesis is sometimes cited; this claims that the language one speaks influences the way one thinks. Thus, a "better" language should allow the speaker to think more clearly or intelligently or to encompass more points of view; this was the intention of Suzette Haden Elgin in creating Láadan, the language embodied in her feminist science fiction series Native Tongue. A constructed language could also be used to restrict thought, as in George Orwell's Newspeak, or to simplify thought, as in Toki Pona. In contrast, linguists such as Stephen Pinker argue that ideas exist independently of language. Thus, children spontaneously re-invent slang and even grammar with each generation. (See The Language Instinct.) If this is true, attempts to control the range of human thought through the reform of language would fail, as concepts like "freedom" will reappear in new words if the old vanish.
Proponents claim a particular language makes it easier to express and understand concepts in one area, and more difficult in others. An analogy can be taken from the way various computer languages make it easier to write certain kinds of programs and harder to write others.
Another reason cited for using a constructed language is the TelescopeRule; this claims that it takes less time to first learn a simple constructed language and then a natural language, than to learn only a natural language. Thus, if someone wants to learn English, some suggest learning Basic English first. Constructed languages like Esperanto and Ido are in fact often simpler due to the typical lack of irregular verbs and other grammatical quirks. Some studies have found that learning Esperanto helps in learning a non-constructed language later (see Propaedeutic value of Esperanto).
The ISO 639-2 standard reserves the language code "art" to denote artificial languages. However, some constructed languages have their own ISO 639 language codes (e.g. "eo" and "epo" for Esperanto, or "ia" and "ina" for Interlingua and "qny" for Quenya).
The earliest non-natural languages were less considered "constructed" as "super-natural" or mystical. The Lingua Ignota, recorded in the 12th century by St. Hildegard of Bingen is an example; apparently it is a form of private mystical cant (see also language of angels). An important example from Middle-Eastern culture is Balaibalan, invented in the 16th century. Kabbalistic grammatical speculation was directed at recovering the original language spoken by Adam and Eve in Paradise, lost in the confusion of tongues. The first Christian project for an ideal language is outlined in Dante Alighieri's De vulgari eloquentia, where he searches for the ideal Italian vernacular suited for literature. Ramon Llull's Ars magna was a project of a perfect language with which the infidels could be convinced of the truth of the Christian faith. It was basically an application of combinatorics on a given set of concepts. During the Renaissance, Lullian and Kabbalistic ideas were drawn upon in a magical context, resulting in cryptographic applications. The Voynich manuscript may be an example of this.
Renaissance interest in Ancient Egypt, notably the discovery of the Hieroglyphica of Horapollo, and first encounters with the Chinese script directed efforts towards a perfect written language. Johannes Trithemius, in Steganographia and Polygraphia, attempted to show how all languages can be reduced to one. In the 17th century, interest in magical languages was continued by the Rosicrucians and Alchemists (like John Dee). Jakob Boehme in 1623 spoke of a "natural language" (Natursprache) of the senses.
Musical languages from the Renaissance were tied up with mysticism, magic and alchemy, sometimes also referred to as the language of the birds. The Solresol project of 1817 re-invented the concept in a more pragmatic context.
The 17th century saw the rise of projects for "philosophical" or "a priori" languages, such as:
These early taxonomic conlangs produced systems of hierarchical classification that were intended to result in both spoken and written expression. Leibniz had a similar purpose for his lingua generalis of 1678, aiming at a lexicon of characters upon which the user might perform calculations that would yield true propositions automatically, as a side-effect developing binary calculus. These projects were not only occupied with reducing or modelling grammar, but also with the arrangement of all human knowledge into "characters" or hierarchies, an idea that with the Enlightenment would ultimately lead to the Encyclopédie. Many of these 17th-18th century conlangs were pasigraphies, or purely written languages with no spoken form or a spoken form that would vary greatly according to the native language of the reader.
Leibniz and the encyclopedists realized that it is impossible to organize human knowledge unequivocally in a tree diagram, and consequently to construct an a priori language based on such a classification of concepts. Under the entry Charactère, D'Alembert critically reviewed the projects of philosophical languages of the preceding century. After the Encyclopédie, projects for a priori languages moved more and more to the lunatic fringe. Individual authors, typically unaware of the history of the idea, continued to propose taxonomic philosophical languages until the early 20th century (e.g. Ro), but most recent engineered languages have had more modest goals; some are limited to a specific field, like mathematical formalism or calculus (e.g. Lincos and programming languages), others are designed for eliminating syntactical ambiguity (e.g., Loglan and Lojban) or maximizing conciseness (e.g., Ithkuil, Arahau).
Already in the Encyclopédie attention began to focus on a posteriori auxiliary languages. Joachim Faiguet in the article on Langue already wrote a short proposition of a "laconic" or regularized grammar of French. During the 19th century, a bewildering variety of such International Auxiliary Languages (IALs) were proposed, so that Louis Couturat and Leopold Leau in Histoire de la langue universelle (1903) reviewed 38 projects.
The first of these that made any international impact was Volapük, proposed in 1879 by Johann Martin Schleyer; within a decade, 283 Volapükist clubs were counted all over the globe. However, disagreements between Schleyer and some prominent users of the language led to schism, and by the mid 1890s it fell into obscurity, making way for Esperanto, proposed in 1887 by Ludwik Lejzer Zamenhof. Ido, made public in 1907, was a reform of Esperanto. Interlingua, the most recent auxlang to gain a significant number of speakers, emerged in 1951, when the International Auxiliary Language Association published its Interlingua-English Dictionary and an accompanying grammar.
Loglan (1955) and its descendants constitute a pragmatic return to the aims of the a priori languages, tempered by the requirement of usability of an auxiliary language. Thus far, these modern a priori languages have garnered only small groups of speakers.
Artistic languages, constructed for literary enjoyment or aesthetic reasons without any claim of usefulness, begin to appear in Early Modern literature (in Pantagruel, and in Utopian contexts), but they only seem to gain notability as serious projects from the 20th century. A Princess of Mars by Edgar Rice Burroughs was possibly the first fiction of the 20th century to feature a constructed language. Tolkien was the first to develop a family of related fictional languages and was the first academic to publicly discuss artistic languages, admitting to A Secret Vice of his in 1930 at an Esperanto congress. (Orwell's Newspeak should be considered a parody of an IAL rather than an artistic language proper.)
By the turn of the 21st century, it had become common for science-fiction and fantasy works set in other worlds to feature constructed languages, or more commonly, an extremely limited but defined vocabulary which suggests the existence of a complete language, and constructed languages are a regular part of the genre, appearing in Star Wars, Star Trek, Stargate SG-1, Atlantis: The Lost Empire, and the Myst series of computer adventure games. The most famous of these is the Klingon language from Star Trek, which has a bona-fide vocabulary and a full set of functional grammar rules.
Various paper zines on constructed languages were published from the 1970s through the 1990s, such as Glossopoeic Quarterly, Taboo Jadoo, and The Journal of Planned Languages. The CONLANG Mailing List was founded in 1991, and later split off an AUXLANG mailing list dedicated to international auxiliary languages. In the early to mid 1990s a few conlang-related zines were published as email or websites, such as Vortpunoj and Model Languages. The CONLANG mailing list has developed a community of conlangers with its own customs, such as translation challenges and translation relays, and its own terminology. Sarah Higley reports from results of her surveys that the demographics of the CONLANG list are primarily men from North America and western Europe, with a smaller number from Oceania, Asia, the Middle East, and South America, with an age range from thirteen to over sixty; the number of women participating has increased over time. More recently founded online communities include the Zompist Bulletin Board (ZBB; since 2001) and the Conlanger Bulletin Board. Discussion on these fora includes presentation of members' conlangs and feedback from other members, discussion of natural languages, whether particular conlang features have natural language precedents, and how interesting features of natural languages can be repurposed for conlangs, posting of interesting short texts as translation challenges, and meta-discussion about the philosophy of conlanging, conlangers' purposes, and whether conlanging is an art or a hobby. Another 2001 survey by Patrick Jarrett showed an average age of 30.65, with the average time since starting to invent languages 11.83 years. A more recent thread on the ZBB showed that many conlangers spend a relatively small amount of time on any one conlang, moving from one project to another; about a third spend years on developing the same language.
Group collaboration has apparently become more common in recent years, as constructed language designers have started using Internet tools to coordinate design efforts. NGL/Tokcir was an early Internet collaborative engineered language whose designers used a mailing list to discuss and vote on grammatical and lexical design issues. More recently, The Demos IAL Project was developing an international auxiliary language with similar collaborative methods.
Several artistic languages have been developed on different constructed language wikis, usually involving discussion and voting on phonology, grammatical rules and so forth. An interesting variation is the corpus approach, exemplified by Madjal (late 2004) and Kalusa (mid-2006), where contributors simply read the corpus of existing sentences and add their own sentences, perhaps reinforcing existing trends or adding new words and structures. The Kalusa engine adds the ability for visitors to rate sentences as acceptable or unacceptable. There is no explicit statement of grammatical rules or explicit definition of words in this corpus approach; the meaning of words is inferred from their use in various sentences of the corpus, perhaps in different ways by different readers and contributors, and the grammatical rules can be inferred from the structures of the sentences that have been rated highest by the contributors and other visitors.
A special example for this kind of language is Simplish: the German Artist Ulli Purwin tried to set a focus on (what Germans call) 'Anglicisms' - in a humorous way. Everyone is invited to increase the vocabulary: from 'ââtist' to 'ørn'...