Silence: separate silent space from universal spell prevention

SRD 5.2.1 · Spell decisions

Before casting

At the table

1. Maintain Concentration on a 20-foot-radius Sphere centered on a chosen point within range.
2. No sound can be created within or pass through it; creatures entirely inside are Deafened, and entirely enclosed creatures or objects have Thunder immunity.
3. Check a proposed spell’s components and its own description before deciding whether it can operate there.

Example decision

A creature inside the silent sphere proposes a spell with a Verbal component. No feature removes that component. Can it cast that spell there?

No; casting a spell with a Verbal component is impossible there.

Silence explicitly forbids casting a spell that includes a Verbal component in the sphere. Speaking more loudly does not overcome a rule that prevents sound. For a spell without that component, check its remaining requirements and any specific interaction: Message, for example, separately lists magical silence as a barrier.

Watch for this mistake

The source qualifies Deafened and Thunder immunity with being entirely inside the sphere. Keep that spatial requirement distinct from the rule that sound cannot pass through the area.

Ask the table

Where is the creature relative to the sphere, and what components and special wording does its spell require?

Source spell

Level 2 Illusion (Bard, Cleric, Ranger) Casting Time: Action or Ritual 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 has Immunity to Thunder damage, and creatures have the Deafened condition while entirely inside it. Casting a spell that includes a Verbal component is impossible there.

Source: SRD 5.2.1, 162. Online guide.