Step 1: Add a % spell failure chance to all player spells (meaning spells cast from sp, and ones cast from scrolls) when under the effects of the "red alert" harried debuff.
Step 2: Add spells like Blindness/Deafness and Sphere of Silence to the game, along with Vocalize and other spells that allow for casting under the effects of silence. Deafness would add a % spell failure chance due to the caster's inability to hear his/herself speak.
Step 3: Profit, if you happen to be a melee. Growl in frustration if you happen to have a significant reliance on your blue bar.