Babel's Curse

One creature you can see must make a Wisdom saving throw. If the saving throw fails, the creature is cursed and becomes incapable of producing intelligible speech for the duration of the spell. The creature is also unable to cast spells with a verbal component. At the end of each of the creature’s turns, it can repeat the saving throw. A successful save ends the spell. A spell that removes a curse can also end Babel’s curse.
Enhancement: If you cast Babel’s curse with a 5th-level or higher spell slot, the creature is also unable to understand spoken language for the duration of the spell. If you use an 8th-level or higher spell slot, the duration becomes permanent and the creature can’t make saving throws to end the effect.