I'm entering a little late...forgive the delays. As Jackie mentioned, I do have some ideas about the deaf issue, relating to how they think and in what form.
It might seem appropriate to assume that since Germans think in German, the French think in French, that those who are native users of sign language would think in pictures. This, however, is not the case (or so I understand, not being deaf myself). However, the deaf do think using a visual foundation, not an auditory foundation.
American Sign Language (the only manual language I know) is not merely iconic or mimetic. The language has methods it uses (through handshapes, movement, facial expression, etc) to communicate abstract concepts that do not have an immediate visual connection. When deaf people think (and sometimes I think in this vein, too), they think in sign language. When deaf people talk to themselves, they do it in sign language. And I can attest that my deaf brother does not talk in his sleep; he signs (and quite illegibly, if indeed that adverb can be ascribed to a non-written language).
As good evidence, I would present Helen Keller herself. Her ability to think in pictures may have been hampered by her blindness, but she surely could think in either signs or in braille or in tactile movement.
Brandon
