The historical Jesus is to be distinguished from the gospel portraits of him. Traditions about Jesus were circulated by word of mouth for many years after Jesus' death.
Oral tradition is fluid.
The oral mentality remembers, not the precise words, but the core of what was said. Jesus possibly spoke Greek as a second language. The oral tradition exhibits little interest in biographical data about Jesus. At least two decades separate the death of Jesus from the first written records. Forty years elapsed after the death of Jesus before the first canonical gospel was composed.