A couple of weeks ago, I did a little snooping about who were hearing the apostles in their own language. Never did learn what languages those people were, but learned where they were from. The most northern spot was Crimea. That same bit of land Putin was trying to steal from the Ukraine a few years ago. The most eastern spot was India. Western? West of Egypt! (I think Jerusalem might have already been the most southern spot, since the nations named were never more-south.) Add to that, Judea was part of the Roman Empire by then, so that means the religious influences also had some Roman and Greek in there.
Sure. Most believed in gods, but not GOD! Yahweh wasn't even a big hit in Egypt or Syria. (Syria was also present in that group. Back then it was called Mesopotamia.) You cannot say they all knew about Yahweh! Jerusalem was an important trade center at the time. They hosted the known world. Given the list included people from that whole very large area (most of the Mediterranean Sea, clear up to close to Russia, and all the way over to India), nope. They weren't all Jews. Most of them weren't, or Luke wouldn't have listed ten non-Jewish nations.
My mind is still spinning on how large an area those nations encompassed, so hope you don't mind if I copy-paste what I learned of who they were and where they were from. Truly amazing because that whole area is besiege by such turmoil 2000 years later still!
Parthians -- Between the Tigris and India. They were the trade routes between the Grecco-Roman Empire and Asia. (Iran and Iraq today.)
Medes -- The real Aryans. S.W. and S. of the Caspian, N.W. and N. of Persia, W. of Parthia and the salt desert of Iram, E. of Armenia and Assyria. (Iran today.)
Elamite -- A district southeast of Babylon, on Persian Gulf. (Iran today.)
Mesopotamia -- Syria. Situated within the Tigris–Euphrates river system, in modern days roughly corresponding to most of Iraq plus Kuwait, the eastern parts of Syria, Southeastern Turkey, and regions along the Turkish–Syrian and Iran–Iraq borders.
Judea -- Home turf, so I expected them to be there that day.
Cappadocia -- An extensive province in eastern Asia Minor, bounded by the Taurus mountains on the South, the Anti-Taurus and the Euphrates on the East, and, less definitely, by Pontus and Galatia on the North and West. Highest mountain, Argaeus, over 13,000 ft. above sea-level; chief rivers, the Pyramus now Jihan, Sarus now Sihon, and Halys now the Kuzul; most important cities, Caesarea Mazaca, Comana, Miletene now Malatia, and Tyana now Bor. At Malatia the country unrolls itself as a fertile plain; elsewhere the province is for the most part composed of billowy and rather barren uplands, and bleak mountain peaks and pastures. (Now Turkey and beyond.)
Pontus -- North of Cappadocia. Actually, it sounds like it's sometimes considered a part of Cappadocia. The area was named after the river, Pontus River. Which then became the Euxine River. Which we now know today as Kerch Straits. That's toward the top of the Black Sea, (which used to be called The Euxine Sea.) It's that little body of water separating Crimea from the rest of the Ukraine. And, a few years ago, Russia tried to steal it back, because it's still strategic for its ability to ship cargo all around the Black Sea. I'm not sure of the historical era, but these people were, at one time, known for something else. The Amazon women were from Pontus. (Ukraine today.)
Asia -- Not the continent we think of today, but definitely part of that continent. At the time the NT was being written, Asia was the most affluent providence of the Roman Empire. The largest cities sound familiar -- Adramyttium, Assos, Cnidus, Ephesus, Laodicea, Miletus, Pergamos, Philadelphia, Sardis, Smyrna, Thyatira, and Troas. (The boundaries changed often, but much of it is Turkey today.)
Phrygia -- Now Western Turkey
Pamphylia -- A small region in the southern part of Turkey.
Egypt -- Which is the same Egypt, but now part of the Roman Empire.