Ido

Ido is a reformed and somewhat simplified version of Esperanto
developed by a number of linguists and scientists including Dr Louis
de Beaufront, Professor Louis Couturat, Professor Richard Lorenz, Professor
Wilhelm Ostwald, Professor L. Pfaundler, and Professor Otto Jespersen.

The main reforms in Ido are in orthography – no diacritics are used,
and in the marking of the accusative, which is used only if necessary.
There are also differences in vocabulary and affixes. For those already
familiar with Esperanto, Italian, Latin or any of the other Romance
languages, Ido is easy to learn.

Other changes in Ido include the introduction of gender-neutral nouns with
optional endings to indicate gender, and a gender-neutral third person pronoun
(lu); elimination of the need for adjectives to ‘agree’ with the nouns they
qualify, and of some difficult consonant clusters, such as ksc and kz.

The estimated number of people who speak Ido is between two and five
thousand, and interest in the language has increased thanks to online
activity, however no accurate statistics for the number of Ido speakers
exist.