I thought the explanation was pretty clear, co/cum means "with" not on an equal footing but in a subordinate fashion as Paul says:
(Col 1:24): "Now I rejoice in my sufferings for your sake, and in my flesh I complete what is lacking in Christ's afflictions for the sake of his body, that is, the church,"
Mary's sufferings are efficacious towards the redemption of man because they are wholly rooted in the redemptive graces of Christ and are perfectly united to His redeeming will. Similarly, as Mediatrix, the Mother of Jesus does not "rival" Christ's mediation but rather participates in the one mediation of Jesus Christ. Imagine water from a reservoir reaching the people through a system of aqueducts or channels. By analogy, Jesus is the infinite "reservoir" of all grace, which is distributed to us through Mary .... as she gave birth to Jesus. Jesus, the one mediator, does not exclude secondary, subordinate mediators.
This is pretty clear, I think its easier to explain than the Assumption, but that's just me.
That may well be -- to the informed Catholic. Other Catholics, and most protestants, will only see "co-redemptrix," and assume that that means that Mary's sufferings were somehow equal to Christ's and necessary for our redemption.
A clearer term might be in order.
Just the view of this Protestant....
No. "Cum" has no implication of a subordinate position. If I'm "with you", we're together, shoulder to shoulder.
Anyway, the vast majority of Catholics are not aware of the nuances of Latin roots of words. Defining this doctrine will elevate Mary to a "co-equal" status with Her Son in the minds of the Catholics, and all Protestants.
"Co-Redemptrix" is simply not going to work. We'll have to come up with some other English description for this doctrine.
Isaiah 63:1-6
God's Day of Vengeance and Redemption
Who is this coming from Edom,
from Bozrah, with his garments stained crimson?
Who is this, robed in splendor,
striding forward in the greatness of his strength?
"It is I, speaking in righteousness,
mighty to save."
Why are your garments red,
like those of one treading the winepress?
"I have trodden the winepress alone;
from the nations no one was with me.
I trampled them in my anger
and trod them down in my wrath;
their blood spattered my garments,
and I stained all my clothing.
For the day of vengeance was in my heart,
and the year of my redemption has come.
I looked, but there was no one to help,
I was appalled that no one gave support;
so my own arm worked salvation for me,
and my own wrath sustained me.
I trampled the nations in my anger;
in my wrath I made them drunk
and poured their blood on the ground."
There is no justification for using the term redemtrix in any way, especially if it's preceded by the prefix co-.
co- prefix [ME, fr. L, fr. com-; akin to OE ge-,
perfective and collective prefix, OIr com- with] 1 : with : together : joint : jointly
2 : in or to the same degree
3 a : one that is associated in an action with another : fellow : partner
b : having a usu. lesser share in duty or responsibility : alternate : deputy
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