While I think it's unlikely Jesus used Latin at the Last Supper, how in the world could you know? Just how old are you? 

He may well have used Hebrew, as that was used in prayer at that time. And he may well have used Greek, which was widely spoken in the Holy Land at that time, including by many Jews. We really don't know what language(s) he spoke, either in ordinary life, or in prayer. Again, if you claim to know for certain, please explain just *how* you know.

And in any case, all that is irrelevant to the point I made earlier.

You also claim to know just what languages early Christians spoke at the Eucharist in the first centuries. There's no way you can know this. How could you?

Of course their were churches prior to Constantine. Who told you otherwise?