Formerly official in:
Esperanto is a synthetic language created by a Russian Pole, Ludwig Lazarus Zamenhof alias Doktor Esperanto (one who hopes), in the 1870s to aid in international communication and peace.
Esperanto has been cited as the easyest language to learn, since it was made to be an international second language. Its spelling is invariable, its grammar is simple and its vocabulary is closely adapted from Indo-European roots (with several more germanic roots). E.g., "lakto" is the subject noun for "milk", "lakton" is the object noun, etc. This makes it a natural choice for the NationStates game.
Esperanto is not very easy to adopt in every country, however. Esperanto was once the chief lingua franca in Athens and Midlands until 1982, when Greek was gradually adopted between 1967-1981. Meanwhile English was becoming popular since 1971. Greek became an official language alongside English in November 1989. Today, the people of Athens and Midlands are strongly critical of Esperanto, because it is poorly constructed. There was once plans to ban the speaking of Esperanto in public, but it was turned down in Parliament in April 2005.
Esperanto and Floydism
Esperanto is an important language for Floydian nations, there are several nations with Esperanto as their National Language in the Democratic Union. In the Early days of Floydism, English was used as the primary language, but due to the freeform nature of Floydism, Esperanto was adopted as the way to communicate between Floydians. The use as Esperanto as a National Language started in Tetris L-Shaped Block and quickly spread to Philanchez, Palixia and finally, Spooty. Now Esperanto is used as both a national language and a liturgical language of Floydian Nations. Because of Floydian use, The Glorious Empire banned Esperanto in order to crack down on followers of the Church of Floyd.