What is the X in X-mas?
style of singing in which a leader alternates with a chorus, especially in liturgical chant. Responsorial singing, also known as call-and-response, is found in the folk music of many cultures-e.g., Native American, African, and African American. One example from the rural United States is the lining out of hymns in churches: a leader sings a hymn line, which is then repeated by the congregation. Responsorial singing of the psalms was practiced in ancient Hebrew and early Christian liturgies. Compare antiphonal singing.