In Response to a Long Comment, a Longer Post · Second Long Comment, Second Longer Post
I am not answering all, because some things, I don't disagree with, some things I already answered, I get the feeling, and some things, I don't know. My main contention is only that Romanides (whom I have read, or perhaps it was the summary by Metallinos), is inaccurate in stating the earliest Roman Patricians spoke Greek.
"All Roman histories were in Greek by earlier Greek historians first. Latin written histories came WAY later."
Well, because Latin literature, even to the Patricians, was not a known concept before they met the Greeks and before they had had a taste of Greek literature.
If the Patricians had known Greek all along, why didn't they give Rome a Greek literature?
"Archaic Greek (Mycenean) is found all over Italy as far north as Rome."
Found? Epigraphically? I missed out on that one!
"The 12 Tables are written in Latin for the plebs. The Patricians knew their laws by heart, since childhood, and spoke perfect Greek since childhood, in their homes, etc. Julius Caesar spoke mostly Greek, says Seutonius!"
Suetonius. Twelve Tables are earlier.
449 BC - 100 BC = 349 years before Caesar was born.
"Latis is also believed to be an Aeolism, and this was believed to be a fact by the people who lived 2000 years ago. I think they knew more about their own history and culture than today's so called language experts and linguists."
Greeks were not usually great linguists. Compared to Persian, Latin actually sounds more Greek, like it has -os (which became -us only later) in the masculine main declinsion, where even Old Persian may have dropped the -s and changed the -o- to -a- ... and of all the Greek dialects that the Greeks had available, the Aeolian was closest.
Feminine main declinsion has α not η and this rules out Attic and Ionian. Leaves either Doric or Aeolic. While Persian has "kê" for "who" the Latin "quis" (and some close by languages even pis) is closer to Greek ... again, what dialect? Attic and I think Doric too has "τις" but Aeolic has "πις"
"But the 12 Tables are based on earlier, much older, Greek laws, written in Greek, in Athens and other city states, the Eraoi Deltoi, as Romanides quotes this from Dionysius and Livy both confirming this."
I look up Livy, you are right that at least Athens was involved.
 the patricians, who would propose measures advantageous to both parties, [p. 197]and such as might tend to the equalization of liberty.” This proposal the patricians did not reject. They said that “no one should propose laws, except some of the patricians.” When they agreed with respect to the laws, and differed only with respect to the proposer; ambassadors were sent to Athens, Spurius Posthumius Albus, Aulus Manlius Publius Sulpicius Camerinus; and they were ordered to copy out the celebrated laws of Solon, and to become acquainted with the institutions, customs, and laws of the other states of Greece.
 The ambassadors had now returned with the Athenian laws; the tribunes pressed the more urgently, that a commencement should at length be made of compiling the laws.
 Next to these were considered the three ambassadors who had gone to Athens; at the same time that the honour might serve as a recompence for so distant an embassy; at the same time they considered that persons acquainted with the foreign laws would be of use in digesting the new code of regulations.
But to get laws from there, ambassadors would have needed to speak Attic, not Mycenaean.
"The true spirit of Rome and all of its legacy is bilingualism in Greek AND Latin (modern forms of course)."
This is true, but I am afraid that this is not so from day 1.
Rome has two faces, like Janus. It is both "the fourth beast of horrible aspect" (Antiochus IV Epiphanes was a vassal of the Republic) and (probably) "ο κατεχων" (possibly even) "το κατεχον".
The latter starts with Julius Caesar, a more normal monarch than the decemviri ("ten horns" in the Apocalypse).
That Greek is used in the Latin liturgy (not saying Bergoglio has a business celebrating it, he could be invalidly ordained even as priest), is normal. Christ was born in the bilingual Roman Empire of the Caesars, not in the Republic of the Ten Men. Or of Scipio Africanus and Asiaticus (who made Antiochus' father a Roman vassal).
Hans Georg Lundahl
Monday after Trinity