Esperanto (/ˌɛspəˈrɑːntoʊ/ or /ˌɛspəˈræntoʊ/) is the world's most widely spoken constructed international auxiliary language. It is the only such language with a population of native speakers, of which there are perhaps several thousand. Usage estimates are difficult, but two recent estimates put the number of active speakers at around 100,000. Concentration of speakers is highest in Europe, East Asia and South America. The Universal Esperanto Association has more than 5,500 members in 120 countries. The language has also gained a noticeable presence on the internet in recent years, as it became increasingly accessible on platforms such as Duolingo.