sailorlum pointed out in prof_snape that the words being sung by the choir in that HBP deleted scene (where Severus is standing so moodily and dramatically, among other things) are these:

In Noctem

Carry my soul into the night
May the stars light my way
I glory in the sight
As darkness takes the day

Ferte in noctem animam meam
Illustrent stellae viam meam
Aspectu illo glorior
Dum capit nox diem

Cantate vitae canticum
Sine dolore actae
Dicite eis quos amabam
Me numquam obliturum

Sing a song, a song of life
Lived without regret
Tell the ones, the ones I loved
I never will forget
Never will forget


I don't know if this was written specifically for the film, and I'm guessing in any case they meant it to foreshadow what's about to happen to one Albus Dumbledore, but still. *shivers*