Esperanto is a constructed (or 'artificial') language created by L.L. Zamenhof in the 1870s and 1880s. Zamenhof envisaged Esperanto as an artificial lingua franca that would facilitate easier global communication.
Ido is a constructed language which has been derived from Esperanto.
Esperanto grammar, including its syntax, is very regular, with little morphological variation. For example, every tense only has one conjugated form of the verb for all persons. There is also no grammatical gender, which means that all nouns have the same article (la). All nouns end in -o in the subject form and -on in the object form, and similarly all adjectives in -a or -an. Moreover, most antonyms of a word are formed just by adding the prefix mal- to the original word. So, for example, nova means "new", while malnova means old.
However, Esperanto grammar also includes features which are rare in Indo-European languages. An example of this is the explicit distinction between transitive and intransitive verbs, i.e. verbs with or without a direct object. For example, while la domo brulas means 'the house burns', mi bruligas la domon means 'I burn the house', incorporating -ig- into the verb to redundantly indicate that the verb has an object. Similarly, since word order can also indicate the role a word or phrase plays in a sentence, the -n indicating the accusative case is redundant.
Despite his intention to make Esperanto a global language, Zamenhof chose to derive the greater part of its vocabulary from the Indo-European language family, especially from the Romance languages and some other branches such as the Germanic and Slavic. Only a small part of Esperanto vocabulary has been borrowed from other language families, such as the Uralic languages, or other individual languages, such as Japanese.
Today, users of the language number at least in the tens of thousands, of whom a few are said to be native speakers. However, the dominance of several natural languages in the world, especially English, has meant that Esperanto is yet to emerge as a true global tongue.
For Esperanto speakers there are several international organizations, of which the Universal Esperanto Association is the most important. Moreover, there also exists literature and music in Esperanto, as well as Esperanto radio stations.