- Esperanto is the most widely spoken constructed international auxiliary language. The name derives from Doktoro Esperanto, the pseudonym under which L. L. Zamenhof published the first book of Esperanto, the Unua Libro, in 1887. The word esperanto means 'one who hopes'. Zamenhof's goal was to create an easy and flexible language that would serve as a universal second language to foster peace and international understanding.
- Although no country has adopted the language officially, it has enjoyed continuous usage by a community estimated at between 100,000 and 2 million speakers for over a century. By most estimates, there are approximately a thousand native speakers.
 Online translators:
- Traduku ( en ⇄ eo translator )
- Tradukilo ( en ⇄ eo translator )
- Apertium (unstable) ( es ⇄ eo translator )
 About Esperanto
- Information about Esperanto
- Learn Free! (a dozen courses for learning Esperanto, available in many languages and for beginners to advanced speakers)
- Programo-Kurso! (free multimedia computer program in 23 languages for teaching yourself Esperanto)
- Trovu La Ringon Perditan (multi-lingual group for translating the game)
- free online tutorial in Esperanto
- Esperanto.net! (Multilingual Information Center)
- Videoj (100 clips en Youtube)