yo·del 
(yōdl)
(yōdl)v. yo·deled, yo·del·ing, yo·dels or yo·delled or yo·del·ling
v.intr.
To sing so that the voice fluctuates rapidly between the normal chest voice and a falsetto.
v.tr.
To sing (a song) by yodeling.
n.
A song or cry that is yodeled.
[German jodeln, from German dialectal jo, exclamation of delight, of imitative origin.]
yodel·er n.