I was after a means of permanently restoring the ability for the slaves to talk. This symbolises the reversal of their enslavement.
The suggestions included:
- 3rd level - the dark wanderer's proposed analog to Remove Blindness / Deafness
- 4th level - Restoration
- 5th level - Psionic power Restore Extremity - specifically re-grows limbs, like arms and legs.
- 6th level - Heal - general purpose healing of the blind, sick, and the lame.
- 7th level - Regeneration, Limited Wish - will re-grow or heal anything.
- 8th level - Polymorph Any Object - massively over-powered for this application.
I thought the dark wanderer's suggestion of a 3rd level spell, analogous to Remove Blindness/Deafness, was a bit too cheap. The spell description reads:
Remove blindness/deafness cures blindness or deafness (your choice), whether the effect is normal or magical in nature. The spell does not restore ears or eyes that have been lost, but it repairs them if they are damaged.
I would consider the slave's tongues to be "lost", not "damaged". So a 3rd level spell analogous to Remove Blindness/Deafness isn't powerful enough.
Jack Lesnie also suggested the 5th level psionic power Restore Extremity. This restores entire arms and legs, so it's certainly powerful enough to restore a tongue.
I conclude from the above that 3rd level spells aren't powerful enough, and 5th level spells are more powerful than needed.
Therefore, I will take the middle ground and allow a 4th level spell to restore a tongue.
Creating a new spell specifically for this purpose would only clutter the spell list, so I will allow Restoration (Clr 4) to re-grow tongues and similar size body parts, like fingers and toes. Regrowing bigger body parts, like hands, arms, and legs, would require Restore Extremity at 5th level.
The party doesn't have 4th level spellcasting yet, so for the time being they will have to use one of the numerous "low-tech" alternatives (sign language, chalkboards).
This gives the party a good roleplaying reason to learn sign language, which may be useful for stealthy party communication in the very sneaky, underhanded, and back-stabby world of Morrowind.