"Antiphon" refers to a call and response style of singing. It originated in Christian music and ritual, where a response is offered by choir or congregation to a preceding psalm or other text. In this work, there are several call and response motifs.
In the CD recording of this work, soprano and alto voices are located on stage left and stage right respectively. The separated projection of each voice is a great plus for the recording. For ensemble purposes it is easier for the sopranos and altos to stand side by side; however, as the title suggests, antiphonal stage setting will provide a more effective musical experience.
As in the introduction, the melody is written within both voices, appearing and disappearing from one to the other. Visually connecting notes of the melody with phrase markings should clarify the moving melody line.