Synonyms for Trill:

n.

babble, click, blow, ding, crunch, buzz, grate, cough, burble. cock-a-doodle-doo, birdsong, shriek, song. carry a tune, harmonize, sing out, sing along, sing, chant, burst/break into song, serenade, croon, vocalize. drumroll, discord, mode, lilt, drumming, chord, music, dissonance, crescendo, harmony. communication (noun)
shake.
cry (noun)
meow, caw, moo, whinny.
quaver (noun)
whistle, roll, wave, sound, twitter.
trill (noun)
quaver, shake, warble.
ululation (noun)
yelp, cuckoo, cackle, meow, crow, mew, snarl, honk, quack, purr, neigh, hoot, roar, caw, ululation, growl, bray, twit, bay, grunt, bellow, squawk, chatter, howl, call, snort, chirp, warble, gobble, bawl, whinny, bark, cry, moo, cluck, coo, squeal, bleat.

v.

ululate (verb)
yelp, cuckoo, cackle, meow, crow, mew, snarl, honk, quack, purr, neigh, hoot, roar, caw, ululate, growl, bray, twit, bay, grunt, bellow, squawk, chatter, howl, call, snort, chirp, warble, gobble, bawl, whinny, bark, cry, moo, cluck, coo, squeal, bleat.
warble (verb)
roll, quaver, shake, sound.

Other synonyms:

sing. cry
sing out.
Other relevant words:
drumroll, birdsong, drumming, harmony, crunch, whistle, grate, ding, cough, dissonance, sound, croon, music, chord, mode, harmonize, serenade, shake, sing, quaver, cock-a-doodle-doo, roll, chant, discord, vocalize, crescendo, blow, burble, babble, lilt, buzz, click, song, twitter, shriek, wave.