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 "excerpt": "Ido is a constructed international auxiliary language created in 1907 as a reformed version of Esperanto, still spoken by an estimated 2,000 to 5,000 people.",
 "snippet": "Ido is a constructed international auxiliary language created in 1907 as a reformed version of Esperanto, still spoken by an estimated 2,000 to 5,000 people.",
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 "markdown": "# Ido\n\n**Ido** is an international auxiliary language, a constructed language of the reformed-[Esperanto](https://www.edgepedia.org/esperanto) type, created in 1907 by a group of European scholars on the basis of an anonymous project whose author used the pseudonym \"Ido\" (*ido* in Esperanto means \"descendant\"), which then became the name of the language<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup>. It was designed as a revision of Esperanto intended to remove features its reformers saw as obstacles to easy learning, and it remains one of the most prominent of the languages descended from Esperanto.\n\n| Key fact | Detail |\n|---|---|\n| Type | International auxiliary language; a reformed Esperanto, classified as a schematic (rule-based) rather than naturalistic project<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup> |\n| Created | Project presented October 1907 to the Delegation committee in Paris; named \"Ido\" in early 1908<sup>[2](https://ido-france.ovh/index.php?page=historique)</sup> |\n| Principal figures | Louis Couturat, Louis de Beaufront, Otto Jespersen, Wilhelm Ostwald, Richard Lorenz, L. Pfaundler<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup><sup> • </sup><sup>[3](https://www.omniglot.com/writing/ido.htm)</sup> |\n| Key reforms | No diacritics; accusative optional; no adjective agreement; gender-neutral pronoun *lu*; systematic \"logical\" word derivation<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup><sup> • </sup><sup>[3](https://www.omniglot.com/writing/ido.htm)</sup> |\n| Stress | Penultimate syllable, except infinitives ending in *-ar*, stressed on the final syllable<sup>[4](https://www.idolinguo.org.uk/bgrammar.htm)</sup> |\n| Speakers | Estimated 2,000 to 5,000; no accurate statistics exist<sup>[3](https://www.omniglot.com/writing/ido.htm)</sup> |\n| Oldest journal | *Progreso*, published since 1908<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup> |\n\n## Origin: the Delegation and the reform project\n\nThe [Delegation for the Adoption of an International Auxiliary Language](https://www.edgepedia.org/delegation-for-the-adoption-of-an-international-auxiliary-language) was set up in 1900, and in 1907 it appointed a committee of linguists, scientists, and philosophers to judge the competing schemes<sup>[5](https://interlanguages.net/IdoHist.html)</sup>. In June 1907 the [Delegation](https://www.edgepedia.org/delegation) elected this committee according to its statutes, and in October of that year the members met in Paris, at the [Collège de France](https://www.edgepedia.org/college-de-france), for eighteen long sessions<sup>[2](https://ido-france.ovh/index.php?page=historique)</sup><sup> • </sup><sup>[6](https://www.geocities.ws/idojc/Hist.html)</sup>. Wilhelm Ostwald, the Nobel-winning chemist, presided; Jan Baudouin de Courtenay and Otto Jespersen served as vice-presidents, and Louis Couturat and Léopold Leau as secretaries, with Louis de Beaufront added for his special competence<sup>[2](https://ido-france.ovh/index.php?page=historique)</sup>.\n\nThe committee concluded that only two schemes deserved consideration: Zamenhof's Esperanto, unchanged since its launch in 1887, and Idiom Neutral, developed by the old Volapük Academy. Its decision was to accept Esperanto, but with major reforms along the lines of an anonymous project submitted under the pseudonym \"Ido\"<sup>[5](https://interlanguages.net/IdoHist.html)</sup>. In early 1908, after the Esperantist linguistic committee refused to apply these modifications, the Delegation named the new language \"Ido\" and published the first manuals and dictionaries<sup>[2](https://ido-france.ovh/index.php?page=historique)</sup>. The Delegation dissolved on 31 July 1910, having founded Uniono por la Linguo Internaciona (ULI) to develop and propagate the language<sup>[2](https://ido-france.ovh/index.php?page=historique)</sup>.\n\nThe anonymous author was soon unmasked as Louis de Beaufront, who had represented the international Esperanto organization before the committee; together with the French philosopher Louis Couturat and their colleagues, he set to work perfecting the scheme<sup>[5](https://interlanguages.net/IdoHist.html)</sup>. A critical account of the episode contends that the final choice was made by only four members of the Permanent Commission, Couturat, de Beaufront, Jespersen, and Leau, two of whom were secretly Ido's authors<sup>[7](https://www.ido-france.ovh/arkivi/Verite_sur_la_Delegation.htm)</sup>.\n\n## Grammar and design reforms\n\nIdo differs from Esperanto by greater closeness to the [Romance languages](https://www.edgepedia.org/romance-languages) in vocabulary and by special \"logical\" rules of word formation<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup>. The accusative ending, obligatory in Esperanto, is optional in Ido: it may mark an object when an unusual word order could create ambiguity, but it is not required in ordinary speech or writing<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup><sup> • </sup><sup>[8](https://www.linguacommons.com/language-learning/con-lang/ido)</sup>. Adjectives do not agree with the nouns they qualify, adjectival agreement being eliminated entirely<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup>.\n\nThe orthography uses the [Latin alphabet](https://www.edgepedia.org/latin-alphabet) without any superscript diacritical marks, so text can be printed, typed, or transmitted without modification; there are no accented letters, and the alphabet matches English<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup><sup> • </sup><sup>[4](https://www.idolinguo.org.uk/bgrammar.htm)</sup>. Ido also introduced gender-neutral nouns with optional endings to indicate gender and a gender-neutral third-person pronoun *lu*, and it removed difficult consonant clusters such as *ksc* and *kz*<sup>[3](https://www.omniglot.com/writing/ido.htm)</sup>.\n\n**Word formation** was the issue at the center of the Ido controversy. Ido imposes consistent rules on the endings that transform a word from one meaning or part of speech to another, simplifying the amount of vocabulary a learner must memorize<sup>[9](https://www.fact-archive.com/encyclopedia/Ido_language)</sup>. Couturat, the author of Ido, took a prescriptive attitude toward word formation, while the partisans of Esperanto defended a descriptive stance; the controversy stimulated scholarly interest in planned languages and helped found the discipline of interlinguistics<sup>[10](https://www.researchgate.net/publication/292617254_Word_formation_and_planned_languages)</sup>. The CALS reference catalog lists about 14,000 roots in Ido's vocabulary<sup>[11](https://cals.info/language/interlingua%2Bido/)</sup>.\n\n## Schism and decline\n\nPublication of the Ido project split the [Esperanto movement](https://www.edgepedia.org/esperanto-movement): a reform-minded wing of 10 to 20 percent supported Ido, while the rest remained loyal to Esperanto<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup>. ULI and an Academy of the language were established in 1909<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup>. The first half of the 1920s was a period of growth for the idist movement, which also underwent social renewal with the appearance of workers' idist organizations; international idist conferences were held regularly from 1921<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup>.\n\nThe movement then weakened from within. A drive for further reforms arose among idists, and carrying those reforms out deprived the language of stability and sharply reduced its number of adherents<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup>. Individual defections compounded the losses: Otto Jespersen, an early proponent, left the movement in 1929 to publish his own planned language, Novial<sup>[12](https://journals.linguisticsociety.org/booknotices/?p=1662)</sup>. The idist movement was suspended during the Second World War and reactivated from the early 1950s, though on a much smaller scale<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup>.\n\n## Ido today\n\nAt the beginning of the 21st century Ido is represented by small groups in Great Britain, Spain, Italy, the Netherlands, Portugal, Russia, the United States, France, Germany, Switzerland, Sweden, and other countries<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup>. Fiction in the language, both original and translated, and works in various fields of knowledge exist, and lexicography has been thoroughly developed; the oldest journal, *Progreso*, has appeared since 1908<sup>[1](https://old.bigenc.ru/linguistics/text/2000466)</sup>.\n\nEstimates of the speaking population run from 2,000 to 5,000 people, and no accurate statistics exist; online activity has increased interest in the language<sup>[3](https://www.omniglot.com/writing/ido.htm)</sup>. The community remains active in writing and conversation: Ido and Esperanto are similar enough to be nearly mutually intelligible in many situations, and Ido retains a continuous century-long written tradition alongside a small but living community<sup>[8](https://www.linguacommons.com/language-learning/con-lang/ido)</sup>.\n\n## References\n\n1. [Идо, Большая российская энциклопедия (С. Н. Кузнецов), том 10, Москва 2008](https://old.bigenc.ru/linguistics/text/2000466)\n2. [Historique de la langue internationale Ido, Ido-France](https://ido-france.ovh/index.php?page=historique)\n3. [Ido language, alphabet and pronunciation, Omniglot](https://www.omniglot.com/writing/ido.htm)\n4. [Basic Grammar of the International Language Ido, idolinguo.org.uk](https://www.idolinguo.org.uk/bgrammar.htm)\n5. [History of the International Language Ido, interlanguages.net](https://interlanguages.net/IdoHist.html)\n6. [History of Our Language (Ido), by Prof. Otto Jespersen, 1912](https://www.geocities.ws/idojc/Hist.html)\n7. [The Truth about the Delegation in 1907, Ido-France archive](https://www.ido-france.ovh/arkivi/Verite_sur_la_Delegation.htm)\n8. [Ido, LinguaCommons](https://www.linguacommons.com/language-learning/con-lang/ido)\n9. [Ido language, Fact-Archive online dictionary](https://www.fact-archive.com/encyclopedia/Ido_language)\n10. [Klaus Schubert (2015), Word-Formation and Planned Languages, De Gruyter Mouton](https://www.researchgate.net/publication/292617254_Word_formation_and_planned_languages)\n11. [CALS: Comparing Interlingua and Ido](https://cals.info/language/interlingua%2Bido/)\n12. [An Elementary Grammar of Ido, Book Notices, Linguistic Society of America](https://journals.linguisticsociety.org/booknotices/?p=1662)\n\n---\n*Topic: Encyclopedia › Society and history › Languages and linguistics › Languages and dialects › Named languages by region › Named languages overview*\n\n*Initially written Sep 17, 2026 · Reviewed: Oct 25, 2026 · Edited: Oct 15, 2026; Oct 25, 2026 · Last review: Oct 25, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n",
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