The Agnus Dei and the Kyrie

Agnus Dei

Qui tollis is the surprise: qui is a relative pronoun, but tollis is second person, "you take". The Lamb is being spoken to, so the clause takes the person of the one addressed. English has to add "you who".

Miserere is the imperative of the deponent misereor. Classical Latin gives it a genitive (miserere mei, have mercy on me, Psalm 50:3); the Agnus Dei uses the dative nobis.

At a requiem in the 1962 Missal the endings change: dona eis requiem twice, then dona eis requiem sempiternam: grant them rest, grant them eternal rest.

Kyrie eleison: Greek, not Latin

• Kyrie, eleison. Christe, eleison. Kyrie, eleison. - Lord, have mercy. Christ, have mercy. Lord, have mercy.

It is Greek. Kyrie is the vocative of kyrios, lord, and eleison is an aorist imperative, have mercy. Latin can say the same (Domine, miserere), and Rome kept the Greek anyway, probably borrowed from Eastern litanies around the end of the fifth century.

So it is not pronounced by Latin rules: eleison is four syllables, e-le-i-son, and Kyrie three, Ky-ri-e.

Who says the responses

How much the congregation says depends on the kind of Mass:

At a 1962 low Mass the responses belong to the server, who answers for everyone. The dialogue Mass, which spread from the 1920s and was formally encouraged by Rome in 1958, gave them back to the people. Listen to what the room does at one Mass; join in at the next.

Mistakes English speakers make