Last modified: 2005-11-30.

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Paul O. Bartlett <bartlett at panix dot com>

Conlangs and International Auxiliary Languages

"Conlangs" is a generic term for constructed languages, also called planned languages or artificial languages. So-called international auxiliary languages (IALs), of which Esperanto is the best-known, are usually conlangs. (conIAL = constructed international auxiiliary language)

:Here: I have an essay on my thoughts of what factors contribute to the success of a constructed international auxiliary language.

At this :link: and at this :link: James Chandler has a lot of material on the conIAL issue generally, with some tendency of information toward Ido.

:Here: Robin Turner has an essay on international auxiliary languages.



The following several links are also especially fruitful for those wishing to learn more about constructed languages in general. Since the advent of the World Wide Web, so much material has appeared on constructed and auxiliary languages that it is difficult to keep track of it all, and many of the links change without notice. Therefore, it is possible that some of the links on this page may become obsolete without my knowing about them.

This is a :link: to Chris Bogart's conlang file.

At this :link: Richard Kennaway has extensive material on constructed languages.

There is also another :link: here to Jeffrey Henning's page on model languages.

Follow this :link: for some more general information on auxiliary languages.


One major conIAL is Interlingua, first published in 1951 by the International Auxliliary Language Association. Many educated speakers of English and the Romance languages can understand most of an Interlingua text without having studied the language. For the official web pages of the Union Mondial pro Interlingua, follow this :link:. At this :link:, Thomas Breinstrup also has valuable information on Interlingua. (Not surprisingly, some of these pages reference each other.)

A starting point for abundant information about Esperanto on the Web is to follow this :link: to Don Harlow's Esperanto pages (with material in English, Esperanto, and other languages). Another starting point is at this :link:. This :link: will take you to considerable material Ken Caviness has in defense of Esperanto against criticisms and "competitors."

IDO (the name is the Esperanto word for "offspring") developed from Esperanto in the early part of the twentieth century. The proponents of Ido argued that Esperanto could be improved in several ways and proposed the Ido reforms. Many Esperantists did not accept the reforms, and Esperanto and Ido went their separate ways as different international auxiliary languages, although there remains a fair amount of similarity between them. Ido has never developed as large a user base as Esperanto, but there are still those who use and promote it. Follow this :link: to James Chandler's pages about Ido, including links to further information, grammatical material, and vocabularies.


As an editorial aside, and comparing Ido and Esperanto with my limited knowledge, let us suppose that the two languages were being presented today to the world "cold," that is, with neither of them having any history behind them (no speakers, books, or literature, and without regard to personalities or how or by whom they got to be what they are). If I had to select one of the two, I would choose Ido. Just my personal opinion, and without prejudicing any other IALs.

However, it is the case that they are not being presented de novo. Esperanto and Ido (as well as other conIALs) do in fact have a history behind them, as does the entire international auxiliary language movement. Today the IAL movement does not exist in a vacuum. For reasons I point out in my essay on factors of IAL success (referenced above), there may be various factors involved with why one conIAL has, or has had, relatively more success than others, which are not directly dependent on the supposed "quality" of one or another language.

Many IAL advocates would like to see SOME auxiliary language widely used, and they would be willing to go with whatever one seems most likely to to gain acceptance, even if it were not their personal favorite. In this sense, I would say that Esperanto is the clear leader and has been for a long time, despite criticisms of it. Esperanto was not the first horse out of the gates, and it may not be the handsomest nag on the track, but it keeps winning its heats. Therefore, even if my personal preferences were otherwise, I agree largely with the linguist Mario Pei (paraphrasing) that it is more important that people pick some workable language and simply agree to use it than that everybody be happy with the choice. (End of editorial.)


The first constructed auxiliary language of modern times to gain any real, widespread popular support was Volapük, first published in 1879 by Johann Martin Schleyer, a Catholic priest in Germany. Volapük flourished briefly, but then the movement withered somewhat. One of the problems was that Schleyer insisted on maintaining complete proprietary control and settling all issues himself. However, in the 1930's, well after Schleyer's death, Arie de Jong of the Netherlands led a small Volapük revival after introducing some changes, and it is now de Jong's version which is commonly used as "Volapük" by those people who still use the language. Additional information is available at this :link: and at this :link:. A collated list of grammatical forms of revised Volapük is available at this :link:. In character, Volapük is an agglutinative "mixed" language, combining both a priori and a posteriori elements. Volapük gave rise to several offshoots, among them Idiom Neutral and Spokil.

At this :link: David Stark has Latino Moderne, whose vocabulary is based on the Interlingua-English Dictionary but whose grammar differs somewhat from that of Interlingua.

Around the turn of the century, the Italian mathematician G. Peano proposed an auxiliary language constructed by stripping Latin of (nearly) all its inflections. Consequently, it was called Latino sine Flexione. (At times it was also referred to as Interlingua, not to be confused with the Interlingua of the International Auxiliary Language Association.) At this :link: Jay Bowks has information on this language.

In 1907, Stephen Chase Houghton privately published a small book entitled The Master Language. It was a plan for an international auxiliary language based squarely on a modfied Latin vocabulary with English word order in place of the Latin inflectional system. Despite the deplorable name, it was a modest and respectable attempt to devise an auxiliary language with the notable advantage that separate two-way dictionaries would not be needed, as Latin dictionaries already exist for many languages. The entire book, along with a preface and some comments, is available at this :link:. (Houghton may have published a later version, but this has not been available to me for examination.) (At this :link: is a variant of Master caled Latinvlo.)

In 1922, the Estonian polyglot Edgar de Wahl published Occidental. In the late 1940s it also became known by the name InterlinguE (not to be confused with either of two auxiliary languages known by the name InterlinguA). Occidental is a more or less "naturalistic" IAL based on Greco-Latin vocabulary found in western European languages with a somewhat schematised grammar. A primary design intention of Occidental / Interlingue is that it can largely be understood by educated users of western European languages without prior study. Although use of the language never completely died out, it became less used for a period, but recently there has been a revival of interest in Occidental (which Robert Petry also refers to by the neologism Auli-Prim). Some information is available at this :link:.

GLOSA is an IAL based on the original work of Lancelot Hogben in the 1940s, in his project Interglossa. Glosa is interesting among conlangs in that it is a completely analytic language: there are no inflections for noun plurals, verb tenses, genders, and what-not. Somewhat as in English, a word may be used as more than one part of speech. The base vocabulary contains only between 1000 - 2000 words and is derived from Greek and Latin roots, many of which occur in everyday English words and in the international scientific and technical vocabulary. Follow this :link: to further information about this language, including a basic reference on Glosa in English (about 148K, with wordlists and examples).

Lojban, a major constructed language based on predicate logic, had its origin in the project Loglan by James Cooke Brown. Lojban is a team effort of the Logical Language Group, Inc., and is one of the most thoroughly worked out of conlangs. The Group used an algorithm to determine basic vocabulary in order to provide as many mnemonic "hooks" as possible for people of various native languages. Lojban is useful for the study of languages themselves and has been used as an auxiliary language in its own right. (The Group's pages may have information on further uses.) Follow this :link: to extensive information about Lojban. Another source of links to further information on Lojban appears :here:. At this :link: Robin Turner has a "user-friendly" introduction to Lojban. For information about Loglan itself, follow this :link:.

Eurolang, a project of Phil Hunt of the UK, is a language intended for use in the countries of the European Union. One of its goals is that after only a weekend of study, an educated European (or native speaker of a west European language) should be able to read it passively with only minimal use of a dictionary. Follow this :link: for further information about Eurolang. However, the project may be moribund.

In the 1920's, the professional linguist Otto Jespersen published versions of an international auxiliary language he named Novial. Recently a working group has been updating Novial in a project tentatively called Novial 98. Follow this :link: for more information on Novial 98. Marcos Franco has material on a variant of Novial which he calls Novial Pro at this :link:. There is also a link at this site for some information on the language Intal.

Ceqli is an auxiliary language project of Rex May. Ceqli had its origins in some of the concepts of James Cooke Brown's Loglan, but has developed in its own directions under the influence of English and Mandarin. Follow this :link: for further information about Ceqli.

NGL ("Next Generation Language") is an artificial language under development by a group. Follow this :link: for further information about NGL.

Gilo is an auxiliary language project by Alan Giles. Follow this :link: for further information about Gilo.

Folkspraak is a collective project of a group calling itself Der Folkspraakinstitut. "Folkspraak is a planned language designed to facilitate intercommunication amongst members of the various contemporary Germanic languages of northern Europe and other areas." Follow this :link: for further information about Folkspraak.

Sona was published in 1935 by Kenneth Searight in London. He intended it an an "auxiliary neutral language." It is distinctive in that it is an a priori language, built on 360 radicals and 15 particles. Rick Harrison and his collaborators have been placing a version of the book on the world wide web. Some people hope that it might be used as an IAL, whereas others are content to regard it as an elegant and artful constructed language in its own right. Follow this :link: for further information about Sona.

Lingua Franca Nova is the work of C. George Boeree and recent collaborators. It is an auxiliary language "designed to be a particularly simple, consistent, and easy to learn language for international communications." Its phonolgy is simple, and spelling is phonetic. (These two design principles have resulted in slight modifications of otherwise familiar words.) Grammar is relatively simple and resembles something of a blend of English and the Romance languages, with small modifications. Vocabulary seems to be largely Greek, Latin, and modern Romance in origin. Unlike some one-person projects, LFN has a classified vocabulary of approximately two and a half thousand words, with affixes for vocabulary extension. It is generally well presented in the WWW pages, and some people might see in it resemblences to both IALA Interlingua and Glosa. Follow this :link: for more information.

The original Lingua Franca (not to be confused with Boeree's Lingua Franca Nova) was a (perhaps) pidgin-like trade language spoken around the Mediterranean Sea from some time in the Middle Ages to about the mid nineteenth century. Some information is available on it at this :link: and at this :link: (these links may have cross pointers).

Richard Harrison is the principal author of Vorlin, a constructed language which aims at a balance between technical and esthetic criteria. Follow this :link:. Following this :link: will lead you to a lot of other useful source material on conlangs by Rick Harrison.

In 1957, Pham Xuan Thai published in Vietnam an international auxiliary language project called FRATER (Lingua Sistemfrater), or "brotherhood language." I have found this project intriguing, but I think it needs some revision, enhancement, and supplementation. I have called the work I have done on this revision frater2. Follow this :link: for a preliminary description of frater2. The main vocabulary of frater2, if completed, will largely be that of the original FRATER (with the verb system reworked).

Designed by W. John Weilgart, Ph.D., aUI is a philosophical a priori language based on a set of (31) proposed universal semantic primitives, each designated with a simple ideograph, from which words from any culture can be created. Mini-definitions of a word's essential meaning, analogous to chemical formulas, are composed from these elements of meaning. aUI for the first time overcomes the arbitrary nature of existing languages and incorporates an inherently meaningful relationship between Word, Meaning, and Reality, between Sound, Symbol, and Meaning. [From a summary provided to me.] Follow this :link: for further information about aUI.

At this :link: Jay Bowks has his Project Auxilingua to tie together a lot of material on international auxiliary languages. Much of the explanatory matter itself is in Interlingua.