The Centurion's statement would have been made in Latin or Greek, depending on whom he was talking to. Latin would be used by Roman officials (including military) to communicate among themselves, but in the Eastern Empire, Greek was the lingua franca and was the language Rome used to communicate with the people.
A Roman officer would have had little need nor interest in mulling his thoughts in Hebrew or Aramaic.
(For more information on this topic, see my video What Languages Did Jesus Speak?)
What did the Centurion Say?
If we had to choose between the Markan & Lukan statements, I'd suggest the "Son of God" statement is more likely for 2 reasons:
- It is attested by Matthew (Matt. 27:54)
- It is less sensible for Matthew & Mark to change "innocent" to "Son of God"--especially Matthew, who's writing to a Jewish audience--than it is for Luke, writing to a Gentile audience, to replace "Son of God", which would have carried relatively little weight to a polytheistic pagan reader, with "innocent", which effectively makes the overall point (Jesus was sent to His death ultimately for false charges of blasphmey). Luke's audience is less interested in Jewish theology than in knowing whether Jesus was a criminal.
However, this need not be an either/or. Matthew provides us with more detail on this event (and my own work on the Synoptic Problem leads me to the conclusion that Matthew's work is the original). Matthew indicates there were multiple people discussing the matter:
Now when the centurion, and they that were with him, watching Jesus, saw the earthquake, and those things that were done, they feared greatly, saying, Truly this was the Son of God. (Matt. 27:54)
Thus, it is entirely possible that some in the group said one thing, and others said another.
Furthermore, when we recognize that Jesus was originally condemned by the Sanhedrin for claiming to be the Son of God, the statements "He is the Son of God" & "He is innocent" are functionally equivalent:
- If He is innocent, that means His declaration that He was the Son of God wasn't blasphemous
- The only way for it to not be blasphemous is for it to be true.
If Jesus is innocent (as attested by Luke), His declaration to be the Son of God is true.