If you're reading this, in a way you're very lucky. English is spoken as either a first or second languages by anywhere between 800 million and 1.8 billion people on Earth. This means that you'll be able to communicate with a good part of the world's population. An alternate view is that you're very unlucky. If you're a native speaker you're not that likely to have learned a second language. English has become a candidate for the modern lingua franca not because it has the greatest number of native speakers, but because the greatest number of non-native speakers are willing to pick it up. It has occurred to native and non-native speakers alike that this might not be fair. The pushiness - and ultimate temporariness - of dominant languages has caused people to try to come up with a simple, common language that the entire world might learn to allow for basic communication everywhere. The languages have, for the most part, died on the vine.
EsperantoIt made its debut in 1887, the brain-child of Ludovic Zamenhof, a Polish physician. Zamenhof, who was troubled by the language-based conflicts he saw in his homeland, first wanted to reintroduce Latin or Greek, but he found their idiosyncrasies frustrating. After looking into a few languages, he identified stumbling blocks - irregular verbs, unusual spelling, gendered nouns - and created a languages that eschewed all of the messiness of the natural. Esperanto is phonetic, regular, and grammatically simple. In some ways the negative reaction to the idea of Esperanto fueled its growth. The Russian Czar had dreams of an earthly tower of Babel and banned the learning of it by his people. Eastern Europe and China, wary of the growth of English, saw Esperanto as a way to promote a common language that didn't favor any particular nation. Ironically, the language meant to unite everyone got its first kick due to the politics of resentment. Its peace-and-love spirit wasn't embraced in English-speaking countries until, of course, the 1970s.
Although it's, by far, the most popular auxiliary language, Esperanto has proved impractical. Since it's nobody's native tongue, it relies on people's willingness to learn it as a second language. Few people are motivated to do that unless there are already a great deal of people also willing to learn it, and so it seems to be spiraling down, not up. One good kick from people around the world and it might yet become a common language, but to do that it has to overcome its homegrown demons.