In Mosiah 4:2 we find the following:
And they had viewed themselves in their own carnal state, even less than the dust of the earth. And they all cried aloud with one voice, saying: O have mercy and apply the atoning blood of Christ that we may receive forgiveness of our sins, and our hearts may be purified; for we believe in Jesus Christ, the Son of God, who created heaven and earth, and all things; who shall come down among the children of men. (italics added)
Hugh Nibley asks the question, "How could they cry out this long thing with one voice? The answer, as brother Nibley takes many pages to illustrate, is that these actions were part of a ceremony, the great assembly, the national assembly, the coronation of kings. In this ceremony there is a director, or a praecentor. In Greek and Roman times, he was called the stasiarch. Someone would hand him a piece of paper, the emperor would tell him, or someone else would tell him what he wanted the people to chant. He would say, "Now all together" and he would read a line and wave the flag, and they would all chant together. These were formal chants and this was the way it was done. [Hugh W. Nibley, Teachings of the Book of Mormon, Semester 1, p. 470]