Imagine a society at a medieval technological level, with a fully populated town enclosed by stone walls and including a fort.
One day the population wakes up to find none of them can speak, or make any kind of noise verbally. While there may be clergy or nobles or educated merchants with literacy, almost everyone else cannot read or write.
For the purposes of the scenario, nobody can leave the settlement (it's under siege). Any outsiders entering a zone just outside the walls will also lose their ability to speak, but it returns if they leave again.
How will the population inside the settlement cope with daily life, as well keeping the town defended, and how will this change as the siege could last many months?