Tongue Twister

As an action on your turn, you prepare to foil the casting of a spell in range. As a reaction on another creature's turn, you can let loose a vicious tongue twisting enchantment and curse the target's tongue to betray them. If the spell they cast has a somatic component, the caster must make a Charisma Saving Throw equal to their Spell Save DC. Spells foiled in this way do not expend the spell slot of the caster but leave the caster unable to speak nothing but gibberish until the start of their next turn.

If the target is not proficient in Charisma Saving Throws but it has proficiency or expertise in the Performance skill, it can add that bonus to their saving throw.