Throttle
A throttle weapon deals damage only when it is used to grapple a foe, automatically dealing damage with every successful grapple combat maneuver. All throttle weapons are also grapple weapons. While a target is successfully being grappled with a throttle weapon, it cannot use its airways to speak or make vocalizations of any kind (though other forms of making noise work normally).
Source
Armory pg. 30
