The most prosperous were Volapük (1879, Johann Martin Schleyer), Esperanto (1887 Ludwik Lejzer Zamenhof), Latino sine flexione (1903, Giuseppe Peano), Ido (1907, Louis Couturat), Occidental-Interlingue (1922, Edgar de Wahl) and Interlingua (1951, IALA and Alexander Gode), with Esperanto being the only one still gathering a considerable community of active speakers today. Here, the Bliss symbols (1949, Charles K. Bliss)[15] deserve also to be mentioned. These were intended for international communication, but have found their field of application elsewhere, namely as an aid for persons who lack an adequate ability of using ordinary language, because of motorical or cognitive handicaps.