artificial language constructed by the French logician and Esperantist Louis de Beaufront and presented at the Délégation pour l'Adoption d'une Langue Auxiliaire Internationale (Delegation for the Adoption of an International Auxiliary Language) of 1907. The language is a reworking of Esperanto (q.v.), intended by its originator to improve upon what he considered weak points in Esperanto. In fact, Ido takes its name from an Esperanto suffix meaning “derived from”—i.e., derived from Esperanto. Ido allows spellings that are more natural to the average European than spellings in Esperanto, although they are less true to Esperanto's rule of one letter for each sound. It has excluded special accented letters found in Esperanto (ĉ, ĵ, ŝ, ĝ, ĥ) in favour of more familiar forms (ch, j, sh; sounds equivalent to Esperanto ĝ 【English j】 and ĥ 【Greek ch, Russian kh】 are not represented), and it allows qu for Esperanto kw, x for ks, and y for Esperanto j. Its grammar is also similar to Esperanto, but Ido incorporates rather more Romance features—e.g., infinitives in -ar, -er, -ir as in Spanish, plurals of nouns in -i as in Italian, and verb inflections reminiscent of Latin or Interlingua. In the decade or two following its appearance, Ido acquired some popularity, which then declined.