For centuries upon centuries, four procession songs have been part of the Mass.
The Introit - [Entrance]
The Offertory
The Communion - in Latin, Communio.
These are but a line or two long, and are taken from the Psalms, the great songs of the church. You will find the text of them in your Breaking Bread or Missal.
Why are they so short? They may sung in a very florid style with many notes [Melismatic Chant] or only one note per syllable. [Syllabic Chant]. When sung in a florid style they take more time.
And they may be repeated, with alternating verse from Psalms in between the repetitions.
You will find our cantors and choir members singing them in Latin and English.