Arabic as a language didn't exist in the 1st century. It dates to the 6th century or maybe even the 5th
It's ancestor (may be direct or more likely an "aunt language") Nabatean existed at that time
I'm not really sure what is the Nabatean word for the God, but it would be some relationship to El/Al
So to the point, during Pentecost, the Jews from "arabia" would be speaking either Nabatean or a south semitic language (the languages of Yemen), so what word they would have heard? well, firstly they wouldn't have heard God saying "The God", but more like "the lord" and it wouldn't have been Al-illah
"predates our english equivalent" - the english equivalent of Allah would be "The God" not "God".
The Arabic Christians use the word Allah, while Assyrians use the Assyrian word Elaha
“Arabic as a language didn’t exist in the 1st century. It dates to the 6th century or maybe even the 5th
It’s ancestor (may be direct or more likely an ‘aunt language’) Nabatean existed at that time
I’m not really sure what is the Nabatean word for the God, but it would be some relationship to El/Al”
The Nabatean Kingdom was not part of the Roman Empire until early second century and the language would probably be Old Arabic. Hismaic inscriptions of the same era document prayers to God using the word “Allat”.
Like all languages, pronunciations and spellings change over time. But we do have written records that show a continuity from Old Arabic to Arabic. Our English equivalent probably came from the Germanic deity Geats which became Gaut which became God in English, Gott in modern German, etc.
So, yes, the first century Arabic equivalent to the modern Allah was probably a sight variation which is not preserved for us in a written record, but Allah was not some newly invented deity that arrived with Islam.
People are hardwired to believe in a Supreme Deity. The Supreme Deity has different titles in different languages. Islam has bad theology about who the Supreme Deity is, but it does not follow that their title for God is the wrong one in Arabic.
It is proper to argue that Islam does not truly follow/worship/represent “Allah” or the Supreme Deity we call “God” in English. It is not proper to call Allah Satan, as Allah is not a term exclusive to Islam.