holla holla /ˈhɑː.lə/

noun

1. [Archaic] A very loud utterance (like the sound of an animal)  ( bellowing , holla [Archaic] , hollo [Non-standard] , bellow , holler [Informal] , holloa , roar , roaring , yowl , hollering [Informal] )
   a very loud utterance (like the sound of an animal)
    His bellow filled the hallway
   his bellow filled the hallway