Source : Webster's Revised Unabridged Dictionary (1913)

Volapuk \Vol`a*p["u]k"\, n.
   Literally, world's speech; the name of an artificial language
   invented by Johan Martin Schleyer, of Constance, Switzerland,
   about 1879.

Source : WordNet®

Volapuk
     n : one of the first artificial language constructed for use as
         an auxiliary international language; based largely on
         English but with some German and French and Latin roots