The inscription on the cross was presumably written in a language the people reading it would be able to read. This establishes that Hebrew literacy was widespread, not that Hebrew was the daily language of Judaea. In fact, Jesus’ “eli, eli, lama sabachthani!” and numerous other Aramaicisms encoded into the Greek of the New Testament suggests strongly that the normal language of day-to-day conversation was Aramaic.
Eli, Hebrews eli, my God, ( Matthew 27:46), an exclamation used by Christ on the cross.
Mark (15:34), as usual, gives the original Aramaic form of the word, Eloi.
Hebrew literacy was not widespread outside of the Jewish community, and the further one travelled from Jeruslaem the less Hebrew the Jewish community spoke and understood. But around Jerusalem and Judea Hebrew was the language of choice for the nationalistic Jewish community to whom Jesus was sent.
In fact, Jesus eli, eli, lama sabachthani! and numerous other Aramaicisms encoded into the Greek of the New Testament suggests strongly that the normal language of day-to-day conversation was Aramaic.
These few Aramaicisms were the exceptions not the rule. The fact that those few Aramaicisms were left untranslated in the Greek Gospels, ie transferred verbatim, is indicative that the language the Jews spoke everyday was not Aramaic. Otherwise why translate all the rest that Jesus and the people said to each other into the Greek but leave these few Aramaicisms untranslated???
The fact is that just because Jesus mixed some Aramaic into his Hebrew does not mean that He was now speaking Aramaic, anymore than those of us do today when we mix words from other languages into our everyday English. We are still speaking English.