Interlinguistics of interlinguistics are, however, not so constructive, but rather descriptive, comparative, historic, sociolinguistic, or concerned with translation by humans or machines. As for Esperanto, which is the most widely used constructed interlanguage, there is a relatively abundant literature about the language itself and its philology (see Esperantology). Only a few of the many constructed languages have been applied practically to any noteworthy extent. 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
Ludwik Hass to his education. He was released in 1948 and remained in the Soviet Union until he returned to Poland in 1957. On his arrival in Warsaw he astounded a welcoming delegation of students, by announcing that he was a revolutionary who wanted to overthrow the bureaucracy. He then sang "The Internationale" and gave a clenched fist salute. Ludwik Hass Ludwik Hass (1918–2008) was a Polish historian who specialised in the history of Freemasonry in Poland. Hass was born to Jewish parents in Stanisławow. He was brought up in a middle-class family which had been assimilated to polish nationalism. He attended