Source : WordNet®

yodel
     n : a songlike cry in which the voice fluctuates rapidly between
         the normal voice and falsetto
     v : sing by changing register; sing by yodeling; "The Austrians
         were yodeling in the mountains" [syn: {warble}, {descant}]
     [also: {yodelling}, {yodelled}]

yodelling
     See {yodel}