Esperantido is a term used for languages derivatives of Esperanto and a constructed language for describing a language project based on or inspired by Esperanto.
The creator of the Esperanto was the eye doctor L. L. Zamenhof in 1887. He proposed reform in 1894 with several changes, and considered it "Reformed Esperanto".
The most popular project of Esperantido is the Ido, but it is far less popular than the original Esperanto, which continues to be the world's most popular constructed language of all universal language projects.