Six years ago Rorate posted on who is allowed to sing the Passion during Holy Week. The answer, we thought, was pretty clear, but apparently not everyone agreed. Some traditional Latin Masses employed laymen to chant entire parts of the Passion, as performed via the novus ordo.
To that end, the Pontifical Commission "Ecclesia Dei" was consulted on this issue. Here is the response:
To summarize, the privilege to chant the Passion begins at the diaconate level for all three parts of the Passion (except for the turba portion of the synagoga).
