Esperanto and Ido are constructed international auxiliary languages, with Ido being an Esperantido derived from Esperanto and Reformed Esperanto. The number of speakers is estimated at 100 thousand to 2 million for Esperanto, whereas Ido is much fewer at 100 to 1 thousand.

Esperanto was developed by L. L. Zamenhof, who published it in 1887 under the pseudonym Dr Esperanto. It immediately became popular, but soon the members of the movements were making suggestions as to how they thought it might be improved. Zamenhof responded by making a list of possible changes to Esperanto and in 1894 put them before the Esperanto community. If accepted they would create what Dr Zamenhof called a "Reformed Esperanto". This proposed reformed Esperanto is sometimes referred to as Esperanto 1894. However, when the Esperanto community was invited to vote on whether to adopt the proposals, they rejected the proposals by a large majority.

Ido was created around a quarter of a century after Esperanto. The name Ido means "offspring" in Esperanto and was so named by its creators because it was a development of Esperanto. The creation of Ido led to a schism between those who believed that Esperanto should be left as it was and those who believed that it had what they perceived as inherent flaws which made it not quite good enough to be the world's international auxiliary language. Those who opposed change maintained that it was endless tinkering that had led, in their opinion, to the decline of Volapük, a once popular constructed language that had predated Esperanto's publication by a few years. They also cited the rejection of Zamenhof's 1894 reform proposals.

The languages of Esperanto and Ido remain close, and largely mutually intelligible, like two dialects of the same language. Just as dialects of a language are quite often sources of new words for that language through literature, so Ido has contributed many neologisms to Esperanto (especially in poetic substitutes for long words using the mal- prefix).

Summary of differences Aspect Esperanto Ido Example Alphabet uses diacritics(ĉ, ĝ, ĥ, ĵ, ŝ, ŭ)and a digraph(dz) uses digraphs(ch, sh, qu) Translation of chamber, shoe and square: ambro / uo / adrato (Esp.)ambro / uo / adrato (Ido) Gender Originally:masculine by default;feminine optionalMore recently, also:gender-neutral by default;feminine optional gender-neutral by default;masculine and feminine optional Gender of "elephant":elefanto (default [or masc.]) / elefantino (fem.) (Esp.)elefanto (default) / elefantulo (masc.) / elefantino (fem.) (Ido) Antonyms formed by mal- prefix come from natural vocabulary can be formed by des- prefix Translation of "warm" and "cold":varma / varma (Esp.)varma / kolda (Ido) Infinitives -i suffix -ir (past) -ar (present) -or (future) suffixes Translation of "to go":ir (Esp.)ir (Ido) Imperative -u suffix -ez suffix Translation of "go!":ir! (Esp.)ir! (Ido) Plural noun -oj suffix(agglutinative) -i suffix(synthetic) Plural of "house" (domo):dom (Esp.)dom (Ido) Adjectives Agree with nouns Unchanged Translation of "big dogs":granda hundoj (Esp.)granda hundi (Ido) Accusativeform (-n) Mandatory Only when objectprecedes subject Translation of "I drink milk" / "I milk drink" / "Milk I drink":"mi trinkas lakto" / "mi lakto trinkas" / "lakto mi trinkas" (Esp.)"me drinkas lakto" / "me lakto drinkas" / "lakto me drinkas" (Ido) i.e., SVO / SOV / OSV Propernouns Sometimes altered Not altered Translation of "Europe":Eŭropo (Esp.)Europa (Ido) No. ofspeakers c. 100,000–2,000,000 c. 1,000–5,000

History

Calls for specific reforms to Esperanto were made almost from the beginning, and so Dr. L. L. Zamenhof published suggestions for reform in 1894. Publication took the form of a series of four articles (including a list of words singled out for possible change) in La Esperantisto monthly magazine, under the title Pri Reformoj en Esperanto. It was put to the vote whether this should be implemented in full or in part, or reworked or rejected. A big majority voted to reject it outright. Because so many voted no Zamenhof took no further interest in changing Esperanto and concentrated instead on the work of Fundamenta Esperanto.

In 1900 Louis Couturat, a French mathematician, after initial correspondence with Zamenhof created the Delegation for the Adoption of an International Auxiliary Language. The Delegation approached the International Association of Academies, based in Vienna, in 1907, requesting it to choose between the many artificial languages. This request was denied. The Delegation's response was to meet later that year (1907) in Paris as a committee under the chairmanship of Louis Couturat with the intention of deciding the issue themselves.

One of the languages under consideration was, of course, Esperanto. Zamenhof did not give permission to reprint his articles detailing his "Esperanto 1894" suggestions but a reprintPri Reformoj en Esperanto: Artikoloj Publikigitaj de Dro Zamenhof en la Nurnberga gazeto “Esperantisto” dum la unua duonjaro de 1894, kopiitaj kaj represitaj per zorgo de Dro Emile Javal , Coulommiers Imprimerie Paul Brodard, 1907. was made and circulated, perhaps predisposing Committee members to think in terms of a reformed Esperanto. (There were 200 copies, distributed personally.) The Committee began its deliberations to choose an international auxiliary language from among the several entries. Most Esperantists assumed Esperanto would win easily. However, an anonymous entry was submitted at the last moment (against the rules) detailing a reformed version of Esperanto. Louis Couturat as chairman demanded the Committee finalize its business within a month, and only five members were involved in making the final decision. Of the five, one abstained and four voted for Esperanto but said it must be reformed. It later was discovered that the anonymous last-minute entrant was Louis de Beaufront, previously the chairman of the French Esperanto movement and chosen by Zamenhof himself to present the case for Esperanto.

Zamenhof refused to be involved in making changes to Esperanto but a group led by Louis Couturat elaborated on Ido as a "Reformed Esperanto". Louis Couturat polemicised against Esperanto until his early death in a car crash in 1914. His loss was a great setback to the spread of Ido.

Not everyone involved in creating Ido was satisfied with it; many former Idists, such as Otto Jespersen (who created Novial) left the movement, bleeding Ido of leaders.

Of all synthetic auxiliary languages, only Esperanto and Latino sine flexione gained a sizeable following and textual corpus to this day.

Esperanto is based on the Fundamento de Esperanto by L. L. Zamenhof; whereas the grammar of Ido is explained in the Kompleta Gramatiko Detaloza di la Linguo Internaciona Ido.

Modern situation and influence of Ido in Esperanto Since Esperanto has proved to be a living, stable language, nowadays Esperantists are less quick to reject influences from Ido. Probably the most fundamental of these is that Esperantists have copied Idists in clarifying the rules for word derivation. In addition, modern Esperanto has borrowed the suffixes -oz- (meaning "abundant in") and -end- (meaning "required to") from Ido.

Especially poets have used the Ido equivalents of Esperanto's "mal-" word class ("Contrary of").

Proposals for a common gender in Esperanto One difference between the two languages is that Ido has an extra common third person singular pronoun, i.e. that means "he or she". For various reasons, this is seen as desirable in Esperanto too by many Esperantists.

Some Esperantists have suggested as a replacement for all singular 3rd person pronouns. The suggested innovation is called , but the total replacement of li, ŝi and ĝi is seen as too radical. When used as a simple addition to existing pronouns, has phonetic problems ("l" and "r" are pronounced by native speakers of Mandarin or Japanese in such a way that it can be hard to distinguish them – a fact that made Rev. Schleyer omit the "r" from Volapük – and this is especially so if the two words differentiating are and ).

In 1967, however, Manuel Halvelik already included the additional common in Arcaicam Esperantom (keeping as masculine pronoun), thus inadvertently founding .

The third possibility, to keep the common-like aspect of and introduce a new masculine pronoun (e.g. ), is the proposal of the attempts of the -class.

Modern view of Esperantists towards proposed changes The present day attitude is shown by the Esperanto Encyclopedia where it states that reforms, i.e. changing the fundaments of a language, have never been successful neither in Esperanto nor anywhere else, while evolution through use "enriches languages".Enciklopedio de Esperanto, Budapesto 1933, "Reformoj en Esperanto"

Alphabet +Alphabets Esperantoabcĉdefgĝhĥijĵklmnopkvrsŝtuŭv--z Esperanto 1894abz-defg-h-ij-klmnopkvrsctu-v--- Idoabcchdefg-h-iyjklmnopqursshtu-vwxzIPA phonemesabdefghijklmnop/kw/,/kv/rsʃtu(in diphthongs)v/ks/,/ɡz/

Phonology

Ido omits two consonants used in Esperanto, and , opting to use the similar sounds and exclusively. +Esperanto omitted soundsIdo similar soundsĥhĝj Ido's rule for determining stress is regular, but slightly more complex than Esperanto's. In Esperanto, all words are stressed on the penultimate, second-to-last syllable: radio, televido. In Ido all polysyllables are stressed on the second-to-last syllable except for verb infinitives, which are stressed on the last syllable. If an i or u precedes another vowel, the pair is considered part of the same syllable when applying the accent rule, unless the two vowels are the only ones in the word, in which case the "i" or "u" is stressed. +StressIdoEnglishEsperantoRegular:skolo, kafeo, lernas"school", "coffee" and the present tense of "to learn"lernejo, kafo, lernasVerb infinitives:irar, savar and drinkar"to go", "to know" and "to drink"iri, scii, trinkiPreceding i or u:radio, familio and manuo"radio", "family" and "hand"radio, familio, manuoPreceding i or u (with only two vowels)dio, frua "day" and "early"tago, frue

Orthography Esperanto eliminates the letters ‹q›, ‹w›, ‹x›, and ‹y› from the 26-letter Latin alphabet and adds the new letters ‹ĉ›, ‹ĝ›, ‹ĥ›, ‹ĵ›, ‹ŝ› and ‹ŭ›. Ido uses the 26-letter alphabet without changes, substituting digraphs for Esperanto's diacritics. While words in both Ido and Esperanto are spelled exactly as they are pronounced, the presence of digraphs means that Ido does not have the one-to-one correspondence between letters and sounds that Esperanto has. However, Ido's digraphs are more recognizable to speakers of Romance languages and its avoidance of diacritics guarantees that any computer system that supports English could easily be used for Ido.

The Fundamento de Esperanto does allow the use of the digraphs ‹ch›, ‹gh›, ‹hh›, ‹jh›, ‹sh› and the single letter ‹u› instead of the ordinary diacritical letters of Esperanto when those are unavailable. With the advent of computers, another system of surrogate Esperanto writing using ‹cx›, ‹gx›, ‹hx›, ‹jx›, ‹sx› and ‹ux› was introduced. It however remains unofficial.

In general, the letter () in Esperanto becomes h or k in Ido. The letters ĝ and ĵ are merged into j (which has the sound of "s" in "leisure") while ĉ, ŝ, ŭ, ks/kz, and kv respectively become ch, sh, w, x, and qu.

Morphology

Both in Ido and in Esperanto, each word is built from a root word. A word consists of a root and a grammatical ending. Other words can be formed from that word by removing the grammatical ending and adding a new one, or by inserting certain affixes between the root and the grammatical ending.

Some of the grammatical endings of the two languages are defined as follows:

Grammatical form Esperanto Ido English Singular noun-o (libro) -o (libro) book Plural noun -oj (libroj) -i (libri) books Adjective -a (varma) -a (varma) warm Adverb -e (varme) -e (varme) warmly