Source: Player's Handbook
2nd-level illusion (ritual)
Casting Time:
1 action
Range:
120 feet
Components:
V, S
Duration:
Concentration, up to 10 minutes
For the duration, no sound can be created within or pass through a 20-foot-radius sphere centered on a point you choose within range. Any creature or object entirely inside the sphere is immune to thunder damage, and creatures are deafened while entirely inside it. Casting a spell that includes a verbal component is impossible there.