Warble

Verb

 * 1) to modulate a tone's frequency
 * 2) to sing like a bird, especially with trills.

Noun

 * 1) a lesion under the skin of an animal, caused  by a bot fly
 * 2) (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.

Thesaurus
air, anthem, ballad, bark, bawl, bellow, blare, blat, blubber, boom, bray, breathe, buzz, cackle, call, carol, caw, chant, chatter, cheep, chirk, chirp, chirr, chirrup, chitter, choir, chorus, chuck, clack, cluck, cock-a-doodle-doo, coo, croak, cronk, croon, crow, cuckoo, descant, diapason, do-re-mi, drawl, drum, exclaim, flute, gabble, gaggle, gasp, gobble, growl, grunt, guggle, hiss, honk, hoo, hoot, hum, hymn, intonate, intone, keen, lay, lilt, measure, melodia, minstrel, mumble, murmur, mutter, pant, peep, pip, pipe, psalm, quack, quaver, roar, roll, roulade, rumble, scold, scream, screech, serenade, shake, shriek, sibilate, sigh, sing, sing in chorus, snap, snarl, snort, sob, sol-fa, solmizate, squall, squawk, squeal, strain, thunder, tremolo, trill, troll, trumpet, tune, twang, tweedle, tweedledee, tweet, twit, twitter, vocalize, wail, whine, whisper, whistle, yap, yawp, yell, yelp, yodel

Etymology
From Middle English werble.

Verb

 * Japanese: さえずる
 * Russian: шебетать, заливаться, издавать трели


 * Scottish Gaelic:

Synonyms

 * (to modulate a tone's frequency): trill

Anagrams

 * bawler