Basic Rules, pg. 275
Silence
2-level Illusion
Ritual - does not require spell slot, takes 10 minutes longer
Casting Time: 1 action
Range/Area: 120ft. distance/20ft. area
Components: Verbal, Somatic
Duration: Concentration, up to 10 minutes
Attack/Save: None
Damage/Effect: Control
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.
Available for: Bard, Cleric, Ranger, Druid (Circle of the Land), Warlock (The Undying), Warlock (The Fathomless)