Esperanto is a constructed international auxiliary language. It is the most widely spoken constructed language in the world. The Polish-Jewish ophthalmologist L. L. Zamenhof published the first book detailing Esperanto, Unua Libro, on 26 July 1887. The name of Esperanto derives from Doktoro Esperanto ("Esperanto" translates as "one who hopes"), the pseudonym under which Zamenhof published Unua Libro.

Zamenhof had three goals, as he wrote in Unua Libro:

"To render the study of the language so easy as to make its acquisition mere play to the learner."

"To enable the learner to make direct use of his knowledge with persons of any nationality, whether the language be universally accepted or not; in other words, the language is to be directly a means of international communication."

"To find some means of overcoming the natural indifference of mankind, and disposing them, in the quickest manner possible, and en masse, to learn and use the proposed language as a living one, and not only in last extremities, and with the key at hand."

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