Writing: From 'New Rome'

Here is the beginning of my new novel. This is as far as it has gotten thus far. It is rough, and names for the characters haven't been chosen yet.
"There you go son, something new for you. Try to read the words on that sign."
(name) looked at the sign a few meters away. The letters were greek, but the words were not. Yet, they looked familiar. "Father, could the words have a gallic background?"
"Perhaps. All tribes in the north share a common background. Possibly Norse. What do you think they say?"
"They have a harsh tone to them. But since they are in greek one can assume whoever wrote them wanted them to be translated by us. I would guess they are a warning. That word," at this he pointed at the sign, "appears similar to the gallic word for death."
"Very good, but why warn us? Are we not their enemies?"
"A valid point. But in all our travels no one has harmed the three of us, traveling without a guard."
"We are not dressed as soldiers. We dress like them because we wish to blend in. Just as we try to speak their languages. We do this to show we mean them no harm. And I talk to the head of each village we enter to tell them we wish to learn, and not to fight. Soon word spreads ahead of our path."
The boy looked at his father. "Do you mean they expect us here?"
His father nodded.
"In that case perhaps the sign should be obeyed. Perhaps there is plague here."
"Excellent. As a matter of fact there is a cholera outbreak here. The sign does not say that, but I have heard from those that travel away from here. You did not understand the family we met. They were fleeing the village."
The boy crossed his arms. "And so you lead us into a diseased village for what purpose? To teach me a new language?"
His father laughed and turned to their companion. "You see (name), a boy of six has the nerve to question a parent." He turned back to the boy. "I usually applaud such insolence, and this is no exception. Yet (name), you will have to learn when such behavior will be tolerated, and when such behavior can end your life."
The boy nodded, gently. "I have learned much under you, father."
"Then learn this: Cholera can be avoided."