[bad word] O nobilis nativitas
virgo parit hodie
o patris summa pietas
iam spes datur venie
quia dei filius natus extat in nostra specie
ut mundi delicta tegeret propere.
Triplum
O mira dei misericordia
natus eius qui creavit omnia
nascitur hodie inter animalia
et Maria tamen extat in partu virgo similis
et post partum virgo pia.
Duplum
O decus virgineum
casta parit hodie
o laus celestium
gloria canitur venie
et in terra pax hominibus leticie
iam decantant angeli
o gaudium populi
rite regis pacifici.
Tenor  [bad word] 

Translation
 [bad word] O celebrated nativity, the virgin gives birth
today, o highest love of the father, hope of
forgiveness is given now, because the son
of God is born in our form, that he might
speedily blot out the world's
transgressions.
Triplum
O wondrous mercy of God, who has
created everything; His son is born today
among the animals, and yet Mary in birth
is [bad word] a virgin and is a pious virgin after
birth.
Duplum
O virginal splendour, the chaste lady gives birth today, o praise of the heavens; there is singing about the glory of forgiveness, and now the angels keep singing, "Peace on earth to men of gladness"; o joy to the people of the peace-making king.
Tenor
He has appeared.