Yes, Jesus was sent first to the Jews. But are you forgetting the Samaritans? How about the woman Jesus basically called a dog? Did He not see her faith and heal her? I'm just pointing this out because of the ministry to the Gentiles had already begun. However, I realize they probably spoke aramaic.
Greek was very well known at that time. However the people who would be teaching would be in charge of reading if necessary. Not the illiterates. I seriously doubt there would be a copy in every household like there is today.