Ido () is a constructed language derived from a reformed version of Esperanto, and designed similarly with the goal of being an international auxiliary language (or universal second language) for people of diverse languages. To function as an effective international auxiliary language, Ido was designed specifically to be grammatically, orthographically, and lexicographically regular (and, above all, easy to learn and use). It is the most successful of the many Esperanto derivatives, known as Esperantidoj.

Ido was created in 1907 out of a desire to reform the perceived flaws of Esperanto, a language that had been created 20 years earlier to facilitate international communication. The name comes from the Esperanto word , meaning "offspring", since the language is a derivative of Esperanto. After its inception, Ido was endorsed by some of the Esperanto community. A setback occurred with the sudden death in 1914 of one of its most influential proponents, Louis Couturat. In 1928, the Ido promoter Otto Jespersen quit the movement for his own language Novial.

The popularity of Ido decreased for two reasons: the emergence of further schisms developing from competing reform projects, and a general lack of awareness of Ido as a candidate for an international language. It was not until the spread of the Internet that it began to regain popularity.

Ido uses the same 26 letters as the English (Latin) alphabet, with no diacritics. It draws its vocabulary from English, French, German, Italian, Latin, Russian, Spanish and Portuguese, and is largely intelligible to those who have studied Esperanto.

Several works of literature have been translated into Ido, including The Little Prince, the Book of Psalms, and the Gospel of Luke. As of the year 2000, there were approximately 100–200 Ido speakers in the world.Blanke (2000), cited in Sabine Fiedler "Phraseology in planned languages" , Phraseology / Phraseologie, Walter de Gruyter 2007. pp. 779. Newer statistics place the number of speakers around 1000-5000. As of 2024, 25 individuals in Finland recorded Ido as their native language, according to Statistics Finland.

History Creation The idea of a universal second language is not new, and constructed languages are not a recent phenomenon. During the 12th century Hildegard of Bingen invented a set of words known as the Lingua Ignota. The concept did not attract significant interest until the language Volapük was created in 1879. Volapük was popular for some time and apparently had a few thousand users, but was later eclipsed by the popularity of Esperanto, which was created in 1887. Several other languages, such as Latino sine Flexione and Idiom Neutral were also proposed. It was during this time that French mathematician Louis Couturat formed the Delegation for the Adoption of an International Auxiliary Language.

This delegation made a formal request to the International Association of Academies in Vienna to select and endorse an international language; the request was rejected in May 1907. The Delegation then met as a Committee in Paris in October 1907 to discuss the adoption of a standard international language. Among the languages considered was a new language submitted anonymously after the Committee's deadline by someone using the name Ido. In the end the committee, always without plenary sessions and consisting of only 12 members, concluded the last day with 4 votes for and 1 abstention. They concluded that no language was completely acceptable, but that Esperanto could be accepted "on condition of several modifications to be realized by the permanent Commission in the direction defined by the conclusions of the Report of the Secretaries [Louis Couturat and Léopold Leau] and by the Ido project".

Esperanto's inventor, L. L. Zamenhof, having heard a number of complaints, had suggested in 1894 a proposal for a reformed Esperanto with several changes that Ido adopted: eliminating the accented letters and the accusative case, changing the plural to an Italianesque -i, and replacing the table of correlatives with more Latinate words. However, the Esperanto community voted and rejected Zamenhof's reformed Esperanto, and likewise most rejected the recommendations of the 1907 Committee composed nominally of 12 members. Zamenhof, undoubtedly reminiscent of his experience of the 1894 reforms, strongly supported the Esperanto Committee majority decision. Furthermore, controversy ensued when the "Ido project" was found to have been devised mainly by Louis de Beaufront, whom Zamenhof had chosen to represent Esperanto to the committee (Zamenhof himself could not represent Esperanto as the committee's rules dictated that the creator of a submitted language could not defend it). The Committee's meetings were performed mainly in French, with occasional German. When the president of the Committee asked who was the author of Ido's project, Couturat, de Beaufront and Leau answered that they were not. De Beaufront presented Ido's project and gave a description of it as a better, richer version of Esperanto. Couturat, Leau, de Beaufront and Jespersen were finally the only members who voted, all of them for Ido's project. A month later, Couturat accidentally forwarded Jespersen a copy of a letter in which he acknowledged that de Beaufront was the author of the Ido project. Jespersen was angered by this and asked for a public confession. De Beaufront procrastinated for four months before making a public confession.

It is estimated that some 20% of Esperanto's major promoters and 3–4% of ordinary Esperantists switched to Ido, which from then on suffered constant modifications seeking to perfect it, but which ultimately had the effect of causing many Ido speakers to abandon trying to learn it. Although it divided the Esperanto movement, the schism gave the remaining Esperantists the freedom to concentrate on using and promoting their language as it was. At the same time, it gave the Idists freedom to continue working on their own language for several more years before actively promoting it. The Uniono di la Amiki di la Linguo Internaciona (Union of Friends of the International Language) was established along with an Ido Academy to develop the details of the new language.

Couturat, who was the main proponent of Ido, was killed in an automobile accident in 1914. This, along with World War I, practically suspended the activities of the Ido Academy from 1914 to 1920. In 1928 Ido's major intellectual promoter, the Danish linguist Otto Jespersen, published his own planned language, Novial and ended his promotion of Ido.

Changes Few changes have been made to Ido since 1922.

Camiel de Cock was named secretary of linguistic issues in 1990, succeeding Roger Moureaux. He resigned after the creation of a linguistic committee in 1991. De Cock was succeeded by Robert C. Carnaghan, who had the title from 1992 to 2008. No new words were adopted between 2001 and 2006. After the 2008–2011 elections of ULI's direction committee, Gonçalo Neves replaced Carnaghan as secretary of linguistic issues during February 2008. Neves resigned during August 2008. A new linguistic committee was formed in 2010. In April 2010, Tiberio Madonna was appointed as secretary of linguistic issues, succeeding Neves. In January 2011, ULI approved eight new words. This was the first addition of words in many years. After a series of severe conflicts with the Directing Committee of ULI, Tiberio Madonna was revoked as secretary of linguistic issues on the 26th of May 2013 by official announcement from Loïs Landais, the secretary of ULI.Anunco di la DK pri Tiberio Madonna, ULI-IDO, yahoogroups, May 26th 2013 During January 2022, ULI approved a set of new words (34)Progreso 382 January–April 2022

International Ido conventions ULI organises Ido conventions yearly, and the conventions include a mix of tourism and work.

2024: Madrid, Spain () 2023: Kassel, Germany () 2022: Dessau, Germany, 15 participants() 2019: Berlin, Germany, 15 participants from 2 countries (Information) 2018: Provins, France, 11 participants from 5 countries (Information) 2017: České Budějovice, Czech Republic, 8 participants from 5 countries (Information) 2016: Valencia, Spain, 10 participants from 7 countries (Information) 2015: Berlin, Germany, 14 participants (Information) 2014: Paris, France (Information) 2013: Ouroux-en-Morvan, France, 13 participants from 4 countries (Information) 2012: Dessau, Germany, 12 participants (Information) 2011: Echternach, Luxembourg (Information), 24 participants from 11 countries 2010: Tübingen, Germany (Information) 2009: Riga, Latvia, and Tallinn, Estonia, 14 participants from 7 countries (Information) 2008: Wuppertal-Neviges, Germany, 18 participants from 5 countries (Information) 2007: Paris, France, 14 participants from 9 countries (Information, Photos) 2006: Berlin, Germany, approx. 25 participants from 10 countries (Information) 2005: Toulouse, France, 13 participants from 4 countries (Information) 2004: Kyiv, Ukraine, 17 participants from 9 countries (Information) 2003: Großbothen, Germany, participants from 6 countries (Information) 2002: Kraków, Poland, 14 participants from 6 countries (Information) 2001: Nuremberg, Germany, 14 participants from 5 countries (Information) 2000: Nuremberg, Germany 1999: Waldkappel, Germany 1998: Białobrzegi, Poland, 15 participants from 6 countries 1997: Bakkum, Netherlands, 19 participants from 7 countries 1995: Elsnigk, Germany 1991: Ostend, Belgium, 21 participants 1990: Waldkappel, Germany 1989: Zürich-Thalwil, Switzerland 1987: Eschwege, Germany 1985: Antwerp, Belgium 1983: York, England 1981: Jongny, Switzerland 1980: Namur, Belgium, 35 participants 1979: Uppsala, Sweden 1978: Cambridge, England 1977: Tegel, Germany 1976: Saint-Nazaire, France 1975: Thun, Switzerland 1974: Kyiv, Ukraine 1973: Cardiff, Wales 1972: Chaux-de-Fonds, Switzerland 1971: Trollhättan, Sweden 1970: Luxembourg City, Luxembourg 1969: Zürich, Switzerland 1968: Berlin, Germany 1967: Bourges, France 1966: Biella, Italy 1965: Lons-le-Saunier, France 1964: Kiel, Germany 1963: Barcelona, Spain 1962: Thun, Switzerland 1961: Zürich, Switzerland, participants 1960: Colmar, France 1959: Freiburg im Breisgau, Germany 1957: Luxembourg City, Luxembourg 1952: Berlin, Germany 1951: Turin, Italy 1950: Colmar, France 1939: St. Gallen, Switzerland 1937: Paris, France 1936: Szombathely, Hungary 1935: Fredericia, Denmark 1934: Oostduinkerke, Belgium 1933: Mondorf, Luxembourg 1931: Lauenburg/Elbe, Germany 1930: Sopron, Hungary 1929: Freiburg im Breisgau, Germany 1928: Zürich, Switzerland 1927: Paris, France 1926: Prague, Czechoslovakia 1925: Turin, Italy 1924: Luxembourg City, Luxembourg 1923: Kassel, Germany 1922: Dessau, Germany 1921: Vienna, Austria

Symbols of Ido

The Ido star or Jankó star is the main symbol of Ido. Its six points represent either Ido's six source languages (English, French, Italian, German, Spanish and Russian) or the six continents (excluding Antarctica). The emblem was originally a six-pointed white star on a circular blue background, consisting of two concentric, equilateral triangles, with one vertically flipped. However, this was soon changed due to the similarity it presented with the Star of David, since a true international auxiliary language should not have religious affiliations.

After a search to find an appropriate new symbol, the Ido-Akademio decided on the current Ido symbol, created by their secretary, Paul von Jankó (hence the alternative name the Jankó star). The current Ido Star is a concave isotoxal hexagon, with a vertically flipped equilateral triangle overlaid on top.

Digital era and publications