Today marks Zamenhof Day, the 150th birthday of Dr. Ludovic Lazarus Zamenhof (December 15th, 1859), the inventor of the Esperanto language.
Zamenhof's hope (giving the language its name: the word esperanto is Esperanto for "one who hopes) was that Esperanto would become a universal second language to the world, and would enable anybody, no matter where they were from, to communicate with one another. The international Esperanto-speaking community is estimated at anywhere between 100,000 and 2 million speakers - though they are mainly spread around eastern Europe (in particular the former nations of the old Soviet Union), and in East Asia, particularly mainland China. This has given it something of a reputation of a 'communist' language, even though the tongue has no intended affiliation at all.
The language itself is in many ways in a category of its own - being a planned language (that is, one that was created rather than evolved over time), it does not derive from any particular cultural or ethnic group. There are no regional accents or dialects to worry about, and the grammar is without exceptions - that is, everything follows the rules. Like Spanish, the writing system is entirely phonetic, so if you can speak it, you can read and write it. Even learning vocabulary is made easy due to the 'root' system and the way smaller words are combined to create longer, more specific terms (agglutination) - by learning around 500 root words of vocabulary, you can still have fairly complex and in-depth conversation.
Studies have also shown that a working knowledge of Esperanto is a great advantage if you want to learn another language - mainly due to the simple yet versatile way in which its grammar works.
Happy birthday, Dr. Zamenhof!