Silence

Illusion (Glamer)
Level: Assassin 2, Bard 2, Trickery 2
Components: V, S
Casting Time: 1 standard action
Range: Long (400 ft. + 40 ft./level)
Area: 20-ft.-radius emanation centered on a creature, object, or point in space
Duration: 1 min./level (D)
Saving Throw: Will negates; see text or none (object)
Spell Resistance: Yes; see text or no (object)
Spell Points: 3

The absence of sound makes it obvious something is wrong, but you can’t shout out the warning.

Upon the casting of this spell, complete silence prevails in the affected area. All sound is stopped: Conversation is impossible, spells with verbal components cannot be cast, and no noise whatsoever issues from, enters, or passes through the area. The spell can be cast on a point in space, but the effect is stationary unless cast on a mobile object. The spell can be centered on a creature, and the effect then radiates from the creature and moves as it moves. An unwilling creature can attempt a Will save to negate the spell and can use spell resistance, if any. Items in a creature’s possession or magic items that emit sound receive the benefits of saves and spell resistance, but unattended objects and points in space do not. This spell provides a defense against sonic or language-based attacks.

Augment: If you spend 4 additional spell points, you dramatically modify the spell’s characteristics to turn it into a protection from eavesdropping. Instead of stopping all sound, sound is only prevented from issuing out of the area. Conversations and spellcasting can then occur unhindered within the area, yet no one outside can hear your voices or any other noises from within, including language-dependent or sonic spell effects. Sound passes unhindered through and into this form of Silence.