Use of Esperanto
At the beginning, Esperanto was quite successful. The use of this language grew rapidly in Eastern Europe, Western Europe, the Americas, China and Japan. The first World Congress of Esperanto speakers was held in 1905 in Boulogne-sur-Mer, France. At the time, Esperanto enthusiasts kept in touch through correspondence, periodicals and magazines.
In 1924, the American Radio Relay League adopted Esperanto as the official language of communication, but the use and influence was minimal. Today, Esperanto is the working language of several non-profit organizations, most importantly the World Esperanto Association, which works closely with UNESCO.
Esperanto was never adopted as any country's official language, but in 1968 an artificial island and self-proclaimed state by the name of Rose Island made Esperanto their official language.
Generally speaking, Esperanto never achieved the intended success as the world's number one auxiliary language, but is still used in travel, correspondence, culture, books, radio, TV and, of course, language courses. It's said that one of the reasons for Esperanto's failure is that the language looks, writes and sounds too artificial.
On the other hand, studies have shown, that, not unlike Latin, the learning of Esperanto considerably facilitates the acquisition of other languages. Approximately 2 million people speak and correspond in Esperanto, but about 10 million have a basic or passive knowledge of the language.