The antiphon is a part of the Psalm, hymn or prayer to pray, recite or sing ( especially in the Psalms ) that is interpreted by a person ( 41 antifonero; whose function is to start the prayer or singing indicating with their voices the startup time, speed of prayer or chant and tone of the same. This helps everyone else their prayer in such a way that run on a single voice, with the same intonation, and obviously the same speed. In this case the name of Antiphon refer to " before the 34 sound; or the pattern to continue in prayer, recitation, or singing. ( this makes think that prayer that makes each person and group runs in one voice, which is ultimately the voice of Christ who prays to the father.
