The words of consecration must be spoken in the first person regardless of the language: “This is my Body…This is my Blood.” The priest acts in Persona Christi so his words must be Christ’s.
This answer both proves too much and too little. If the priest is
in persona Christi, then by definition whatever words he speaks are words of Christ. If you mean the words that Christ spoke at the Last Supper, then the problem is that we don’t know them (unless, I guess, he was speaking in Greek) and we don’t know how far, by translation, mistake, or otherwise, we can get from those original words and still be in the clear. So, while trivially valid, this response doesn’t mean much.
With the acceptance of the Chaldean Rite, it can easily be argued the entire canon must be read for a valid consecration.
Hic and hoc are both “this” in English. However in Latin the genders have to agree, so “hoc” refers to “corpus” (body-neuter gender), and “hic” refers to “calix” (chalice-masculine gender).
This is right, except that you don’t quite mean “refers to” here. If the priest says “Hic est enim corpus meum,” the problem isn’t that “hic” is referring to the chalice, it’s that this is bad Latin. It would be a little like saying, “He took the cup, gave him to his disciples, and said…”
So, what’s the result? According to
De Defectibus, “If however one * were to diminish something, or alter the form of the Consecration of the Body and Blood, and in such a change of words the words were not to signify the same, the Sacrament would not be confected” (my translation). I’m in no position to give any kind of canonical response, but my personal view is that erring and saying “His est enim corpus meum” does not change the meaning, and thus signifies what it ought; it’s just a Latin error.
The cynic would say that a priest who would make such an error in such an important part of the Mass should not be saying the Mass in Latin, period, until he is familiar enough with the language that “Hic est corpus”* immediately sounds wrong.
“Hic est corpus” could also mean “Here (in this place) is my body.”