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.