A sudden confused look appears on your target's face as the words coining from his mouth become nonsense.
The subject can't make himself understood through verbal communication.
No matter how hard he tries, he can't speak a language, but only utters nonsense sounds.
His ability to write is unimpeded.
To cast a spell with a verbal component, the subject must succeed on a Concentration check; the DC equals this spell's save DC + level of the spell to be cast.
If you cast bothersome babble on a creature currently affected by a previous casting of the spell, the second spell has a different effect.
As long as both spells' durations last, the subject's speech is physically painful to it.
In any round in which the creature speaks, it takes 1d8 points of damage.
Treat this as continuous damage for the purpose of making Concentration checks to cast spells.
When the first duration ends, this secondary effect is replaced by the normal effect of the spell.