Rorate caeli desuper, et nubes pluant justum: aperiatur terra, et germinet Salvatorem.
“Thaw, heavens from above, and the clouds shall rain the righteous. The earth shall open up and sprout the redeemer.” (Is 45:8)
Click here to listen to an audio of the chant sung by Br. Jacob Berns, OSB, of St. John’s Abbey.
Rorate is probably the best known Gregorian chant from Advent. In the third quarter of the first millenium, when there was no Mass on the 4th Sunday of Advent, Rorate only belonged to Votive Masses in honor of Mary. Then it became the introit for this Sunday, and due to the tradition of Marian Votive Masses by candlelight in Advent, Rorate became the name of any atmospheric Advent services, at least in German speaking regions.
This introit is so impressive and the connection between melodic directions and the text is so obvious that it needs no further explanation.
Desuper in the first line is obviously supposed to be pronounced with the second syllable stressed: de-SU-per. The rules of Latin pronunciation in Carolingian times are different from those of Renaissance Latin, although the latter remain authoritative for the way we learn Latin today. In Gregorian Chant Hebrew names are mostly stressed on the final syllable: Ja-COB, Moy-SES, Abra-HAM, even sometimes Je-SUS and Mari-AM. Words can have more than one stressed syllable, like CAP-ti-vi-TA-tem (where the root syllable of the word CAP-tare remains its emphasis) or BE-ne-di-XIS-ti, which is treated like two words: BE-ne + di-XIS-ti.
The word desuper is regarded here as two words: de + super. De as a monosyllabic word might be stressed or not (we cannot clearly decide it in this case), and super remains its original accent on the first syllable. In Renaissance Latin, desuper would be regarded as a compound word where the accent moves one syllable back so that it is pronounced DE-super. Thankfully the Graduale Novum has given the correct original emphasis: de-SU-per.
By the way: It is the same with the word omnipotens in the Gloria: In the original Gregorian Chant from the Early Middle Ages it is not om-NI-potens, but OM-ni POT-ens.