Phrase Length
Musical phrases that are similar in length to textual sentences usually seem most natural. This is especially true in hymn singing, where text and music are woven together so tightly. Consequently, LONGER musical phrases seem most natural when sung at a quicker tempo, and SHORTER phrases allow for a slower pace.
When hymns with long phrases (such as “Angels We Have Heard on High”--no. 203, Gloria) are sung slowly, the congregation will take extra breaths, making it more difficult to understand the meaning of the text. To prevent this, the tempo should lean towards the faster side.