It is called hollering.
Sense 2:
shout, shout out, cry, call, yell, scream, holler, hollo, squall
utter, emit, let out, let loose
Sense 3:
exclaim, cry, cry out, outcry, call out, shout
express, verbalize, verbalise, utter, give tongue to
Sense 1:
shout
talk, speak, utter, mouth, verbalize, verbalise
Sense 4:
abuse, clapperclaw, blackguard, shout
attack, round, assail, lash out, snipe, assault
A homophone for "shout loudly" is "shout loudly," which sounds the same but is spelled differently and has a different meaning.
loudly
loudly or quickly
A homophone for something round is "pear" and for shout loudly is "bellow."
What is a shout?
loudly
shout
A homonym for something round and shout loudly could be "ball" and "bawl."
to shout out loudly at someone
Wail is another word meaning "shout loudly." The homophone for wail is whale
loudly
bawl and ball