According to the Internet source given below, Bulee "Slim" Gaillard was an American jazz singer, songwriter, pianist, and guitarist, noted for his vocalese singing and word play in a language he called "Vout". In addition to speaking 8 other languages, Gaillaird wrote a dictionary for his own constructed language.
Biography by Wikipedia
This list is arranged in chronological order and contains 5 works by Slim Gaillard (1916-1991). It does not claim to be complete and represents only the number of items located.
Flat Foot Floogie (1938) Words by: Slam Stewart, Bud Green