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 Birkenmajer w przekładzie polskim" (1920) · Mikołaj Kopernik, "O obrotach ciał niebieskich i inne pisma" (2004) · Andrzej Śródka, "Uczeni polscy XIX-XX stulecia". Warszawa 1994, vol. I, p. 155-157 . Paweł Tarasiewicz, Zbigniew Pańpuch, "Birkenmajer Ludwik Antoni", "Powszechna encyklopedia filozofii" vol. I, Lublin 2000 · Władysław Horbacki, "Ludwik Antoni Birkenmajer (1855-1929)". Łódź 1930 Ludwik Birkenmajer Ludwik Antoni Birkenmajer (18 May 1855 - 20 November 1929), Polish historian of science, physicist, astronomer, professor of the Jagiellonian University. Descended from the German family settled in Galicia (Southern Poland) during the time of the Napoleon wars, later a part of the Austrian Habsburg Empire.