Definition of warbled:
(v) :
(transitive) To sing like a bird, especially with trills.
(v) :
(intransitive) To be quavered or modulated; to be uttered melodiously.
(n) :
The sound of one who warbles; singing with trills or modulations.
(v) :
(transitive) To modulate a tone's frequency.
(v) :
(transitive) To cause to quaver or vibrate.
(n) :
(military) In naval mine warfare, the process of varying the frequency of sound produced by a narrowband noisemaker to ensure that the frequency to which the mine will respond is covered.