Alleluia, Pascha Nostrum (Ambrosian Chant)

This piece starts the chorus of women this.  They are singing very melismatically, staying on the "a" vowel at the end of the word "alleluia" for about one minute.  The soloist comes in now and sings for a little while with other text.  She sings "The Paschal Lamb is sacrificed for us, who is Christ the Lord:  he is our God." Her singing could be considered neumatic, for it seems to be in between syllabic and melismatic.  The chorus comes back in to sing a final alleluia which lasts for about a minute and a half on the same word (ultra melismatic again) just as before, only longer.  The song is very peaceful  and florid (there is a lot of movement up and down the melodic range of the song).  This piece is definitely non-metric.