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 Rajchman post-Stalinist period began in 1956. From then on Rajchman went fairly often to Poland, notably to visit his sister who had been dismissed by the authorities from her academic functions. His last visit was to Warsaw in 1963, to visit the public health institute he had founded in 1918. Rajchman died in 1965 due to complications of Parkinson's Disease. Ludwik Rajchman Ludwik Witold Rajchman (1 November 1881 – 13 July 1965) was a Polish physician and bacteriologist. He is regarded as the founder of UNICEF, and served as its first Chairman from 1946 to 1950. He was born to Aleksander