Babble

You target a creature you can see within range, and attempt to make them incapable of speech. The target must succeed a Charisma saving throw or become incapable of normal speech for the duration. A creature under this spell’s effects can speak only in incomprehensible babble, and cannot cast spells that require a verbal component. However, the creature can still read and write languages it knows. Additionally, as a bonus action, you can cause the creature to become incapable of understanding all spoken words, and can drop this effect as a bonus action as well.

While this spell is active, the target makes a Charisma check at the end of each of its turns, suppressing the effects of this spell until the end of its next turn on a success.

At Higher Levels. When you cast this spell with a 6th-level spell slot, the target becomes incapable of communicating with telepathy and similar effects.