It should be remembered that very few people, no matter where they stood on the social/economic ladder, wrote anything to be read by others. There were no magazines, book publishers, or web blogs to send your collected thoughts to. St. Paul and the early gospel writers wrote to specific audiences. The gospels say that Jesus was able to read and write, as stated above, but an interesting question is where was he taught to read and write?
The gospels tell us that after his birth his parents took Jesus to Egypt, out of the reach of King Herod. From the Gospel of Luke we are told that Jesus was back in Palestine by the age of 12, talking with the teachers in Jerusalem. But how long did he live in Egypt, and where did he live in Egypt? Where would St. Joseph have taken his family to live in Egypt? I suppose somewhere where he could practice his trade, live among other Jews and practice his religion, and blend in with a large population in case King Herod sent his spies to search the child out. Many historians make a good case for the great port city of Alexandra. It had a large multi-ethic population, a large Jewish community, and philosophers on every street corner, and if history is to be believed the finest library in the Mediterranean world. It was the New York City of its day, and if Jesus did spend any part of his formative years in the great metropolis he would have been exposes to Hellenistic though and philosophy, and certainly would have been taught to read and write, not only his own ethic tongue but also Greek – the international language of the day. When he is questioned by Pontius Pilate what language did they speak to one another? The Roman governor would not have learned the language of a conquered people, so what language did they speak? Latin, maybe, Greek probably. Jesus probably had a well rounded, Hellenistic education.