Yodel
Part of speech: verb
Definition: To sing (a song) in such a way that the voice fluctuates rapidly between the normal chest voice and falsetto.
Part of speech: noun
Definition: Such a song.
Warble
Part of speech: verb
Definition: to modulate a tone's frequencyto sing like a bird, especially with trills.
Part of speech: noun
Definition: a lesion under the skin of an animal, caused by a bot fly(Military) In naval mine warfare, the process of varying the frequency of sound produced by a narrow band noisemaker to ensure that the frequency to which the mine will respond is covered.