As two actions, you close off the centers of a creature’s mind that deal with communication and social interaction. A creature that you can touch or see within 20 meters must succeed on a Will saving throw or lose knowledge of all languages (including telepathic and body language) and is treated as illiterate for the duration of the spell. Verbal components, if used, are not limited by this spell.
It may still “speak”, and to it they sound completely normal, but to anyone else they appear as complete gibberish.
A creature can repeat the saving throw each minute, ending the effect on itself on a success.
You can target one additional creature for each additional mana or psi expended. The creatures must be within 5 meters of each other when you target them.