The whole discussion about trying to imagine what language spoke at the Last Supper is a red herring to any serious discussion. Certainly this is not an avenue that the Vatican II liturgy document even considers.

What Vatican II did want to use was reliable knowledge about how the early Church celebrated the Eucharist. It is here that place and language are relevant.

As to language, it seems clear that it was celebrated in the language that would be known and understand by the participants.

As to place, it seems clear that initially they used appropriate, but not purpose designed buildings. A key feature of this is that the number of people who gathered for these celebrations was quite small. It is only with the emancipation of the Church under Constantine that you get the phenomenon of great numbers wanting to attend the eucharist and the parallel development of purpose built churches.