The Esperanto suffix -id means child. From bovo (cow) we form bovido (calf); from hundo (dog) we form hundido (puppy). Ido is a child of Esperanto, the first of many Esperanto "reform" projects.
Ido shares much of Esperanto's vocabulary, but replaces many Germanic and Slavic roots with their Romantic counterparts. Nonetheless, speakers of either language can read the other with little difficulty. As in Esperanto, antonyms can be formed by use of the appropriate prefix. One thing that I find intriguing about Ido is that although this sort of antonym formation is both possible and acceptable, Ido also provides a greater number of unique antonyms for common terms than Esperanto does, and in many cases these antonyms are the same as those words which you will find marked literary in an Esperanto dictionary.
In both Esperanto and Ido, adjectives end in -a. But in Esperanto, adjectives must agree in number and case with the nouns they qualify. An adjective in the plural must have the suffix -j appended; and if in the accusative, it will also need -n. Ido does away with adjectival agreement, and requires the accusative only when nonstandard word order is used.
In Esperanto and many other languages, words for people and animals refer either to the male or to neither sex specifically, with the word for the female being derived by use of a suffix. Some say that this is sexist because it is demeaning to the female; I would argue the opposite, that it is demeaning to the male for he has no suffix to call his own. This was probably not a sexism issue in the early 20th century, but it was a logical issue and one that Zamenhof wished to address but for some reason never did. Esperantists have proposed several solutions and some are fairly common today. The Ido approach is this: the root word is epicene (specifies neither sex, or either sex, depending how you look at it); the suffix -ul denotes the male, and -in the female. Thus we speak of an aktoro (actor); if we wish to specify sex, we can refer to this person as an aktorulo or an aktorino. Frato (brother or sister (sibling)) spawns fratulo and fratino; spozo (husband or wife (spouse)) spawns spozulo and spozino. (However, Ido does have some explicit pairs, such as patro and matro.) And the personal pronoun lu (he, she, or it (epicene!)) neatly resolves the old he/she problem.
Ido also reduces the Esperantish adverbial overload problem.
Another advantage in today's wired world is that Ido uses no accented characters. Uncommon characters don't bother me personally, in fact I'm rather fond of some of them and love to use ð (that's a lowercase eth in Latin-1) whenever possible, but it is undoubtedly advantageous to restrict our choice of characters to a common set found on most keyboards.
For these and several other reasons, Ido deserves your consideration. It is very much like Esperanto, but you will probably find that one language fits you better than the other.
"La odoroza sapono" da Fernando Tejón, a story about a
wonderfully sniffy bar of soap which does not shrink with use, but
instead seems to grow a bit... while its users become rather, uh,
tenuous... may be read in
and/or heard in
Podkasto numero 1
of Radio-Idia Internaciona.
(The home pages for those links are