The feast of trumpets is known as the day of shouting because of the Hebrew word תרועה (teruah) Strongs #h8643. It is defined as a trumpet or shofar blast, a shout of alarm or joy. The same word is used for shout in Joshua 6:5, “And when there is a long blast of the ram’s horn and you hear its sound, have all the people give a mighty shout. Then the wall of the city will collapse and all your people will charge straight into the city.”