Babel

Spellcaster can use Babel on one creature it can see. The target must make an Intelligence saving throw. On a failed save the target is unable to use any recognized language. That means it cannot communicate with any other creature, or use spells that have a Verbal Component. 

At the start of its next three turns the target must make an Intelligence Check DC 15. If the creature fails, the spells persists, but if it succeeds the creature is no longer affected.