Comparison between Esperanto and Ido

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There are several main differences between Esperanto and Ido, two constructed languages that have a related past but have since parted ways. Ido was invented in the early 20th century after a schism between those who believed that Esperanto was almost good enough, were it not for inherent features seen by them as flaws that prevented it from being a suitable proposal of international auxiliary language, and those who believed that Esperanto was sufficient as it was, and that endless tinkering with a language would only weaken it in the end.

The languages remain close, and to some extent mutually intelligible. An Italian play which was written with the dialog in two dialects of Italian was translated with Esperanto and Ido representing these two dialects.[citation needed] In the same manner in which dialects often serve as sources for new words through the literature of ethnic languages, so Ido has contributed many neologisms to Esperanto (especially in poetic substitutes for long words using the mal- prefix).

One study conducted with 20 college students at Columbia University circa 1933 suggests that Esperanto's system of correlative words is easier to learn than Ido's. Two other studies by the same researchers suggest no significant overall difference in difficulty of learning between Esperanto and Ido for educated American adults, but the sample sizes were again small: in the two tests combined, only 32 test subjects studied Ido. The researchers concluded that additional comparative studies of Esperanto and Ido are needed.[1]


In 1900 Louis Couturat, after initial correspondences with Esperanto-founder L. L. Zamenhof created the Delegation for the Adoption of an International Auxiliary Language. In 1907 in Vienna, the Delegation met to choose an international auxiliary language to give its approval from among the many candidates which had crept up. Most Esperantists assumed Esperanto would be an easy win. However, when Couturat presented his own pet project, a series of reforms to Esperanto which would eventually become Ido, and demanded an answer within a month, many in the Esperanto movement felt betrayed. Some Esperantists even accuse Couturat and his colleague Louis de Beaufront of a conspiracy saying the International Delegation was simply a front to put forth Ido.

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 Esperanto has received some influence from Ido in areas such as a clarification of the rules for word derivation and suffixes like -oz- ("abundant in") and -end- ("required to").


Ido omits two consonants used in Esperanto, /x/ and /d͡ʒ/, opting to use the similar sounds /h/ and /ʒ/ exclusively.[2]

Ido's rule for determining stress is regular, but more complex than Esperanto's. In Esperanto, all words are stressed on the 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—skolo, kafeo and lernas for "school", "coffee" and the present tense of "to learn", but irar, savar and drinkar for "to go", "to know" and "to drink". If an i or u precedes another vowel, the pair is considered part of the same syllable when applying the accent rule—thus radio, familio and manuo for "radio", "family" and "hand", unless the two vowels are the only ones in the word, in which case the "i" or "u" is stressed: dio, frua for "day" and "early".[3]


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 ĥ in Esperanto becomes h or k in Ido. The letters ĝ and ĵ are merged into j while ĉ, ŝ, ŭ, ks/kz, and kv respectively become ch, sh, w, x, and qu.


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 Ido English Esperanto
Singular noun -o (libro) book -o (libro)
Plural noun -i (libri) books -oj (libroj)
Adjective -a (varma) warm -a (varma)
Adverb -e (varme) warmly -e (varme)
Present tense infinitive -ar (irar) to be going to go -anti (iranti) -i (iri)
Past tense infinitive -ir (irir) to have gone -inti (irinti)
Future tense infinitive -or (iror) to be going to go -onti (ironti)
Present -as (iras) go, goes -as (iras)
Past -is (iris) went -is (iris)
Future -os (iros) will go -os (iros)
Imperative -ez (irez) go! -u (iru)
Conditional -us (irus) would go -us (irus)

Most of these endings are the same as in Esperanto except for -i, -ir, -ar, -or and -ez. Esperanto marks noun plurals by an agglutinative ending -j (so plural nouns end in -oj), uses -i for verb infinitives (Esperanto infinitives are tenseless), and uses -u for the imperative. Verbs in both Esperanto and Ido do not conjugate depending on person, number or gender; the -as, -is, and -os endings suffice whether the subject is I, you, he, she, they, or anything else.

Both languages have the same grammatical rules concerning nouns (ending with -o), adjectives (ending with -a) and many other aspects. However, the relationship between nouns, verbs and adjectives underwent a number of changes with Ido, based on the principle of reversibility. In both languages one can see a direct relationship between the words multa "many" and multo "a multitude" by simply replacing the adjectival -a with a nominal -o, or the other way around.

Some minor differences include the loss of adjectival agreement, and the change of the plural from an agglutinative -j tacked onto the end to a synthetic replacement of the terminal -o with an -i. Hence, Esperanto belaj hundoj ("beautiful dogs") becomes Ido bela hundi. Ido also does away with the direct object ending -n in sentences where the subject precedes the object, so Esperanto mi amas la belajn hundojn ("I love the beautiful dogs") would in Ido become me amas la bela hundi.

Greater differences arise, however, with the derivations of many words. For example, in Esperanto, the noun krono means "a crown", and by replacing the nominal o with a verbal i one derives the verb kroni "to crown". However, if one were to begin with the verb kroni, "to crown", and replace the verbal i with a nominal o to create a noun, the resulting meaning would not be "a coronation", but rather the original "crown". This is because the root kron- is inherently a noun: With the nominal ending -o the word simply means the thing itself, whereas with the verbal -i it means an action performed with the thing. To get the name for the performance of the action, it is necessary to use the suffix -ado, which retains the verbal idea. Thus it is necessary to know which part of speech each Esperanto root belongs to.

Ido introduced a number of suffixes in an attempt to clarify the morphology of a given word, so that the part of speech of the root would not need to be memorized. In the case of the word krono "a crown", the suffix -izar "to cover with" is added to create the verb kronizar "to crown". From this verb it is possible to remove the verbal -ar and replace it with a nominal -o, creating the word kronizo "a coronation". By not allowing a noun to be used directly as a verb, as in Esperanto, Ido verbal roots can be recognized without the need to memorize them.

Ido corresponds more overtly to the expectations of the Romance languages, whereas Esperanto is more heavily influenced by Slavic semantics and phonology.[citation needed]


Ido word order is generally the same as Esperanto (subject–verb–object). The sentence Me havas la blua libro is the same as the Esperanto Mi havas la bluan libron ("I have the blue book"), both in meaning and word order. There are a few differences, however:

  • In both Esperanto and Ido, adjectives can precede the noun as in English, or follow the noun as in Spanish. Thus, Me havas la libro blua means the same thing.
  • Ido has the accusative suffix -n, but unlike Esperanto, this suffix is only required when the object of the sentence is not clear, for example, when the subject-verb-object word order is not followed. Thus, La blua libron me havas also means the same thing.

Unlike Esperanto, Ido does not impose rules of grammatical agreement between grammatical categories within a sentence. Adjectives don't have to be pluralized: in Ido the large books would be la granda libri as opposed to la grandaj libroj in Esperanto.


Although Esperanto and Ido share a large amount of vocabulary, there are differences. The creators of Ido felt that much of Esperanto was either not internationally recognizable, or unnecessarily deformed, and aimed to fix these with more "international" or "corrected" roots. This can sometimes be at the expense of Esperanto's simpler word building process.

Ido, unlike Esperanto, does not assume the male sex in roots such us for family. For example, Ido does not derive the word for waitress by adding a feminine suffix to waiter, as Esperanto does to derive it from neutral to only feminine. Instead, Ido words are defined as sex-neutral, and two different suffixes derive masculine and feminine words from the root: servisto for a waiter of either sex, servistulo for a male waiter, and servistino for a waitress. There are only two exceptions to this rule:[4] First, patro for father, matro for mother, and genitoro for parent, and second, viro for man, muliero for woman, and adulto for adult.[5]

Below are some examples in first Esperanto then Ido with English, French, German, Italian, Spanish and Portuguese for linguistic comparison:*

Esperanto Ido English French German Italian Spanish Portuguese
bubalo bufalo buffalo buffle Büffel bufalo búfalo búfalo
ĉelo celulo cell cellule Zelle cellula célula célula
ĉirkaŭ cirkum around/circa autour de ungefähr/circa circa alrededor, cerca ao redor, em volta
dediĉi dedikar to dedicate dédier widmen dedicare dedicar dedicar
edzo spoz(ul)o husband/spouse époux Ehemann sposo esposo esposo/marido
elasta elastika elastic élastique elastisch elastico elástico elástico
estonteco futuro future futur Zukunft futuro futuro futuro
kaj e(d) and et und e(d) y/e e
lernejo skolo school école Schule scuola escuela escola
limo limito limit limite Limit limite límite limite
maĉi mastikar to chew/masticate mâcher kauen masticare masticar mastigar
mencii mencionar to mention mentionner erwähnen menzionare mencionar mencionar
nacio naciono nation nation Nation nazione nación nação
penti repentar to repent repentir bereuen pentirsi arrepentirse arrepender-se
ŝipo navo boat/ship bateau/navire Schiff barca/nave barco/nave/navío barco/navio
taĉmento detachmento detachment détachement Abteilung distaccamento destacamento destacamento
vipuro vipero viper vipère Viper vipera víbora víbora

*[Note that Spanish, Portuguese, and French are Romance languages, while German and English are Germanic languages. English has also had large influences from French and Latin. In comparison, Esperanto is somewhat more influenced by German vocabulary and Slavic semantics (as in the case of prefix mal-) and has more priority over word compounding by affixes.]


Another principle of Ido is Unasenceso or "one sensedness." This means each Ido root is supposed to correspond to only one meaning. Ido proponents feel that this allows for more precise expression than in Esperanto.


Ido claims the prefix mal- (creating a word with the exact opposite meaning) in Esperanto to be overused as a prefix, and also to be inappropriate since it has negative meanings in many languages, and introduces des- as an alternative in such cases. Ido also uses a series of opposite words in lieu of a prefix. For example, instead of malbona ("bad", the opposite of bona, "good"), Ido uses mala, or instead of mallonga ("short", the opposite of longa, "long"), kurta. Listening comprehension was also given as a reason: the primary Ido grammar book states that one reason for the adoption of the Latin-based sinistra for "left" instead of maldextra (mal- plus the word dextra, or dekstra for "right") is that often only the last one or two syllables can be heard when shouting commands. Esperanto has developed alternate forms for many of these words (such as liva for maldekstra), but most of these are rarely used.[6]

An extreme example of overuse of the mal- suffix.

Esperanto La malbela maljunulino mallaŭte malfermis la pordon al sia kelo kaj malrapide malsupreniris la ŝtuparon.
Ido La leda oldino silence apertis la pordo a sua kelero e lente decensis l'eskalero.
English The ugly old woman quietly opened the door to her basement and slowly descended the stairs.

Most Esperanto words are gender-neutral ("table", "grass", etc.). However, Esperanto assumes the male gender by default in other words, mainly words dealing with familial relationships and some animals. These words can be made female with the use of the feminine suffix. In Ido there is no default gender for normal root words, and one simply adds the corresponding masculine or feminine suffix only when desired. For example, frato means "brother" in Esperanto, but "sibling" in Ido. Ido uses the suffixes -ino ("female", used as in Esperanto) and -ulo ("male", not to be confused with the same Esperanto suffix which means "person"). Thus "sister" is fratino (the same as Esperanto), but brother is fratulo. "Sibling" and other gender neutral forms are especially difficult in Esperanto since Esperanto simply does not have a word for such gender neutral forms. Esperanto does, however, have an epicene prefix that indicates “both sexes together”: ge-. Patro means "father" and patrino "mother"; gepatroj means "parents". In standard usage gepatro cannot be used in the singular to indicate a parent of unknown gender; one would say instead unu el la gepatroj, "one (out) of the parents".

There is a nonstandard suffix in Esperanto that means "male": -iĉo (see Gender reform in Esperanto). There is also an existing prefix, vir-, with the same meaning, used for animals.

A few exceptions exist in Ido's gender system as described above, which avoid its suffix system, for which it was decided that the feminine words were so much more recognizable to its source languages: viro ("man"), muliero ("woman"), patro ("father"), and matro ("mother"). Compare these with Esperanto viro, virino, patro, and patrino, respectively. Ido also has several other neutral-gender words, such as genitoro for "parent". Gepatri in Ido means the same as Esperanto gepatroj (i.e. "parents" of both genders); genitori means "parents" in the English sense, not making any implication of gender whatsoever.

Other words, such as amiko ("friend"), are neutral in Esperanto as well as Ido.


Esperanto adopts a regular scheme of correlatives organized as a table. Ido combines words together and changing word endings with some irregularities to show distinction, which is not as regular as that of Esperanto but is better distinctable by ear.

Relative and


Demonstrative Indeterminate Most


Negative Collective
Esperanto Ido Esperanto Ido Esperanto Ido Ido Esperanto Ido Esperanto Ido
ki- qua, ∅ ti- ita, ∅ i- ula, ∅ irga neni- nula ĉi- omna
Individual Esperanto -u kiu tiu iu neniu ĉiu
Ido -u qua ita ulu irgu nulu omnu
Thing Esperanto -o kio tio io nenio ĉio
Ido -o quo ito ulo irgo nulo omno
Plural Esperanto -j kiuj/kioj tiuj/tioj iuj/ioj neniuj/nenioj ĉiuj/ĉioj
Ido -i qui iti uli irgi nuli omni
Adjective Ido -a qua ita ula irga nula omna
Motive Esperanto -al kial tial ial nenial ĉial
Ido pro pro quo pro to pro ulo pro irgo pro nulo pro omno
Association Esperanto -es kies ties ies nenies ĉies
Ido di di quo di to di ulo di irgo di nulo di omno
Place Esperanto -e kie tie i.e. nenie ĉie
Ido loke ube ibe ulaloke irgaloke nulaloke omnaloke
Time Esperanto -am kiam tiam iam neniam ĉiam
Ido tempe kande lore ulatempe irgatempe nulatempe omnatempe, sempre
Quality Esperanto -a kia tia ia nenia ĉia
Ido -a, speca quala tala ulaspeca irgaspeca nulaspeca omnaspeca
Manner Esperanto -el kiel tiel iel neniel ĉiel
Ido -e, maniere quale tale ule, ulamaniere irge, irgamaniere nule, nulamaniere omne, omnamaniere
Quantity -


Esperanto -om kiom tiom ĉiom neniom tiom
Ido quanta quanta tanta kelka irgaquanta nulaquanta omnaquanta


The Ido correlatives were changed so it would be better distinctable when hearing.

Esperanto Prenu ĉiujn tiujn, kiujn vi volos, kaj lasu ĉiujn tiujn, kiuj ne plaĉos al vi.
Ido Prenez ti omna, quin vu volos, e lasez ti omna, qui ne plezos a vu.
English Take all those, which you want, and leave all those, which you don't like.

note: ĉiujn tiujn, kiuj(n) (all those, which) is more commonly said as ĉiujn, kiuj(n) (all, which) in Esperanto.


Comparison of how long it took to learn the correlatives between Esperanto and Ido was studied at Columbia University circa 1933:

Twenty university students having no particular knowledge of either Esperanto or Ido studied the forty-five correlatives of Esperanto and the corresponding words in Ido, for ninety minutes in each case. Ten studied the Esperanto on January 4 and the Ido on January 5. Ten studied the Ido on January 4 and the Esperanto on January 5.

Following the ninety minutes of study there was a multiple choice test. On January 6 there was a test in which the subjects were required to write the Esperanto and the Ido equivalents of the English words (all, always, each, every, everything, for no reason, how, etc.) Both multiple choice test and recall test for both Esperanto and Ido were repeated on January 23 and April 23. From January 9 to January 23 the subjects had twenty hours of teaching and study of Esperanto, so that only the tests before January 9 are valid for the comparison of the two languages. In these early tests the median number of the 45 multiple choices was 44 for Esperanto and 43 for Ido: the median number recalled correctly from the 45 English words was 32 for Esperanto and 15½ for Ido. The corresponding averages were 28 and 20. The Esperanto system was easier to learn for this group. But the experiment should be repeated with other groups.

— International Auxiliary Language Association, 1933[1]


The pronouns of Ido were revised to make them more acoustically distinct than those of Esperanto, which all end in i. Especially the singular and plural first-person pronouns mi and ni may be difficult to distinguish in a noisy environment, so Ido has me and ni instead. Ido also distinguishes between intimate (tu) and formal (vu) second-person singular pronouns as well as plural second-person pronouns (vi) not marked for intimacy. Furthermore, Ido has a pan-gender third-person pronoun lu (it can mean "he", "she", or "it", depending on the context) in addition to its masculine (il), feminine (el), and neuter (ol) third-person pronouns.

singular plural indefinite
first second third first second third
familiar formal masculine feminine neuter pan-gender masculine feminine neuter pan-gender reflexive
Ido me tu vu il(u) el(u) ol(u) lu ni vi ili eli oli li su on(u)
English I thou/you you he she it he/she/it we you they one
Esperanto mi ci vi li ŝi ĝi ĝi¹ ni vi ili si oni
  1. tiu, though not a personal pronoun, is usually used in this circumstance, because many people have a hard time applying "it" to humans.

It should be noted that ol, like English it and Esperanto ĝi, is not limited to inanimate objects, but can be used "for entities whose sex is indeterminate: babies, children, humans, youths, elders, people, individuals, horses, cows, cats, etc."

Proper nouns[edit]

Esperanto may or may not "Esperantize" names and proper nouns, depending on many factors. Most standard European names have equivalents, as do many major cities and all nations. Ido, on the other hand, treats most proper nouns as foreign words, and does not render them into Ido.

Personal names[edit]

Many common cross-culture European names have Esperanto equivalents, such as Johano (John, Johann, Juan, Jean, etc.), Aleksandro (Alexander, Aleksandr, Alessandro, etc.), Mario or Maria (Mary, Maria, Marie, etc.), among others. Some Esperanto speakers choose to take on a fully assimilated name, or to at least adjust the orthography of their name to the Esperanto alphabet. Others leave their name completely unmodified. This is regarded as a personal choice, and the Academy of Esperanto officially affirmed this proclaiming that “everyone has the right to keep their authentic name in its original orthography, as long as it is written in Latin letters.”[7][8]

Personal names in Ido, on the other hand, are always left unmodified.

Place names[edit]

Most countries have their own names in Esperanto. The system of derivation, though, is sometimes complex. Where the country is named after an ethnic group, the main root means a person of that group: anglo is an Englishman, franco is a Frenchman. Originally, names of countries were created by the addition of the suffix -ujo ("container"), hence England and France would be rendered Anglujo and Francujo respectively (literally "container for Englishmen/Frenchmen"). More recently, many Esperantists have adopted -io as the national suffix, thus creating names more in line with standard international practice (and less odd-looking): Anglio, Francio, nevertheless the suffix remains unofficial.

In the New World, where citizens are named for their country, the name of the country is the main word, and its inhabitants are derived from that: Kanado ("Canada"), kanadano ("Canadian").

Names of cities may or may not have an Esperanto equivalent: Londono for London, Nov-Jorko for New York. Place names which lack widespread recognition, or which would be mangled beyond recognition, usually remain in their native form: Cannes is usually rendered as Cannes.

In Ido, country names must conform to the language's orthography but otherwise are left unchanged: Europa, Peru, Amerika. City names are treated as foreign words (London), except when part of the name itself is a regular noun or adjective: Nov-York (Nov for nova, or "new", but the place name York is not changed as in Esperanto "Nov-Jorko"). This is not a hard and fast rule, however, and New York is also acceptable, similar to writing Köln for the city of Cologne in Germany. South Carolina becomes Sud-Karolina, much in the same way that a river called the "Schwarz River" is not transcribed as the "Black River" in English even though schwarz is the German word for black. However, less well-known place names are generally left alone, so a small town by the name of "Battle River" for example would be written the same way, and not transcribed as "Batalio-rivero". This is because transcribing a little-known place name would make it nearly impossible to find in the original language.


Esperanto and Ido were compared in studies at Columbia University circa 1933:

A question which has been of interest to us is the comparative ease of learning of various artificial languages. The above records are all for Esperanto. Unfortunately we have been able to test only two groups learning Ido. Our test material is available to anyone who wishes to obtain further results. Of our two groups one comprised only four volunteer college students. The other consisted of twenty-eight educated adults who studied Ido for twenty hours as paid subjects in an experiment. We present here the outcome of our study.

Before any study of Ido the initial test scores are higher [than Esperanto], but the gains are less except in one function—aural understanding.

The final scores are practically the same. They are the same in vocabulary, 71.9; in terms of the sum of the three other tests, we have final scores of 44.1 for Esperanto and 45.2 for Ido. These results are, it must be remembered, for a limited number of subjects of able intellect who were working under more or less favorable conditions. Further experimentation, however, will probably bear out our conclusion that there is no great difference in difficulty in the learning of these two particular synthetic languages.

— International Auxiliary Language Association, 1933[1]

Number of speakers[edit]

Esperanto is estimated to have approximately 100,000 to 2 million fluent speakers.[9] In the same manner estimates for the number of Ido speakers are far from accurate, but 500 to a few thousand is most likely.[citation needed] It is also important to note the distinction between the number of speakers compared to the number of supporters; the two languages resemble each other enough that a few weeks of study will enable one to understand the other with little difficulty, and there are a number of people that have learned Ido out of curiosity but prefer to support the larger Esperanto movement and vice versa. The number of participants at the respective international conferences is also much different: Esperanto conferences average 2000 to 3000 participants every year whereas Ido conferences have around 10 participants each year. Each language also has a number of regional conferences during the year on a much less formal basis, and with smaller numbers.[citation needed]


The Lord's Prayer:


Patro nia, kiu estas en la ĉielo,
Via nomo estu sanktigita.
Venu Via regno,
plenumiĝu Via volo,
kiel en la ĉielo, tiel ankaŭ sur la tero.
Nian panon ĉiutagan donu al ni hodiaŭ.
Kaj pardonu al ni niajn ŝuldojn,
kiel ankaŭ ni pardonas al niaj ŝuldantoj.
Kaj ne konduku nin en tenton,
sed liberigu nin de la malbono.


Patro nia qua esas en la cieli,
Vua nomo santigesez;
Vua regno arivez;
Vua volo esez obediata,
Quale en la cielo, anke (tale) sur la tero.
Nia singladi’ panon donez a ni cadie,
E remisez a ni nia debaji,
Quale anke ni remisas a nia debanti,
E ne duktez ni aden la tento,
Ma liberigez ni de lo mala.


Our Father in heaven,
hallowed be your name.
Your kingdom come,
your will be done,
on earth as it is in heaven.
Give us this day our daily bread,
and forgive us our debts,
as we also have forgiven our debtors.
And lead us not into temptation,
but deliver us from evil.


Padre Nuestro que estás en el cielo,
santificado sea tu nombre.
Venga a nosotros tu reino,
hágase tu voluntad,
así en la Tierra como en el cielo.
Danos hoy nuestro pan de cada día,
y perdona nuestras deudas,
como también nosotros perdonamos a nuestros deudores.
No nos dejes caer en la tentación,
y líbranos del mal.


  1. ^ a b c Language Learning: Summary of a Report to the International Auxiliary Language Association in the United States, Incorporated. New York City: Teachers' College, Columbia University. 1933. pp. 12–13. 
  2. ^ De Beaufront, L (2004). "Pronunco dil konstanti e digrami" [Pronunciation of consonants and digraphs] (PDF). Kompleta Gramatiko Detaloza di Ido. pp. 8–11. Retrieved 19 January 2012. 
  3. ^ De Beaufront, L (2004). "Acento tonika" [Tonic accent] (PDF). Kompleta Gramatiko Detaloza di Ido. pp. 11–12. Retrieved 19 January 2012. 
  4. ^ Chandler, James (6 November 1997). "Changes in Ido since 1922". Retrieved 19 January 2012. 
  5. ^ ApGawain, Niklas; P.D. Hugon; J.L. Moore; L. de Beaufront (30 December 2008). Ido For All (PDF). pp. 52, 70. Retrieved 6 February 2012. 
  6. ^ "MAL" (in Esperanto). 9 March 2010. Retrieved 16 April 2011. 
  7. ^ [1] Albaut, André, et al. (1992). AKTOJ de la AKADEMIO III: 1975–1991. Coconnier, Sablé-sur-Sarthe, France. Rekomendoj pri propraj nomoj, pp. 76.
  8. ^ Wennergren, Bertilo (2005). Plena Manlibro de Esperanta Gramatiko. El Cerrito, California, USA: Esperanto-Ligo por Norda Ameriko. ISBN 0-939785-07-2.Propraj nomoj, pp. 499.
  9. ^ Ethnologue report on Esperanto, retrieved 27 March 2010.

External links[edit]