Jubilus
Melismatic closing call of the Alleluia.
What it means
The jubilus designates the long, richly ornamented melodic passage that is sung on the last syllable in the Gregorian Alleluia. Over a single vowel an extended melody unfolds without further text — a chant that detaches itself from language and consists of notes alone. In tradition it counts as the expression of a joy for which words do not suffice.
In the notation
In square notation the jubilus appears as a long sequence of neume groups over a single syllable. Strokes articulate it into sections that are often repeated or varied; this articulation is decisive for performance, because it shows where to breathe and how to phrase.
Musical use
The jubilus has been consequential for music history. From the practice of underlaying such textless melismas with newly written texts, the sequences arose, a genre of its own with a great repertoire; similarly, the adding of text to existing chants led to the trope. The jubilus thus stands at the beginning of a development in which new forms emerge from liturgical melody. At the same time it shows that melodic unfolding without a tie to text was in this music not the exception but a recognized value of expression.
Performance practice
Articulate the long melody into sections and breathe at the marked places, not wherever the air happens to run out. Keep the vowel the same over the whole stretch so that the sound stays unified; changing vowel colours break up the line. Sing without vibrato and with calm tone production, and shape in groups rather than in individual notes. Practise slowly at first to recognize the patterns of repetition — they are the best aid to memory. In alternating singing, settle who takes on the jubilus and where the choir enters.
Bear in mind that the jubilus stands at a prominent place in the liturgy and is not meant as decoration: its length belongs to the matter, and shortening takes away its point. Plan the time in the course accordingly. Keep the vowel the same over the whole stretch and sing without vibrato. When practising, look for recurring turns, because they ease memorizing and show the phrasing.