Allamantantan

When casting this spell on a humanoid the caster can see, it must make a Wisdom saving throw, and does so with advantage if you or your companions are fighting it. On a failed save this humanoid becomes incomprehensible to anyone except the caster for the next hour. When the target tries to speak only gibberish comes out and any other form of communication (writhing, drawing, miming,… ) doesn’t convey the message the target wants to convey. When the spell ends the humanoid knows it was targeted by one of your spells. After this spells effect wears off, the affected humanoid can’t be targeted by the same spell again for 24 hours. This effect doesn’t interfere with this persons use of magic or it’s use of magical or mundane items.

At Higher Levels. When you cast this spell using a spell slot of 3nd level or higher, you can target one additional creature for each slot level above 2nd. All the targeted creatures must be in you're line of sight when you cast the spell. If more than one creature is affected and they're within hearing range of each other. To them it will sound like the other is mocking them with they're inability to speak. They react as their personality dictates, but more likely than normal leaning to the violent sight.