After some debating with my former Sociology classmates we are still wondering what exactly do the blind/deaf/feril think in their minds?
Here is what we know for sure.
When someone goes blind later in life, everything they experience is frozen in their memory. Clothes, faces, and other things look the same in future dreams as they did before they lost their sight.
People born with blindness dream with flashing lights and sounds.
Feril children can have no concept of language or "normal" life at that. So what do they think when they are hungry, scared, or happy? Same goes with the deaf. They can read and understand written and hand language, but what do they think? How do they use their inner monologue? Do they think by visualizing hand movements?
We have been discussing this in detail and really can't come up with an answer.