Colburn's Clandestine Casting

This spell enables spells requiring a vocal component to be cast without having to speak.

Using a clapper-less silver bell, the caster traces a magical glyph in the air then touches the bell to their own lips or the lips of another creature of the caster's choice. The recipient is then able to cast spells silently, though material and somatic components are still required, if the spell calls for them.

The spell lasts for the duration or until dispelled. 

 At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the spell's duration increases by 10 minutes for each slot level above 2nd.