Q: Within the Roman Canon the conclusion “Through Christ our Lord. Amen” appears in parentheses. If the celebrant includes these when praying this Eucharistic Prayer, does the assembly say the Amen?
A: If I remember correctly, Jungmann says that the Amens were never spoken by the people because they entered the canon at a time when the priest recited the words himself quietly. If today’s missal intended the people to say or sing those Amens, it would have indicated it clearly.
I point out in my book At the Supper of the Lamb that the first draft of Eucharistic Prayer IV had two acclamations for the people to sing. The study group pulled the second one, fearing it would never be approved. After the memorial acclamation was approved so quickly, they probably wondered if they removed the second one too quickly.