Was her ability to speak a supernatural thing? Or was it part of some vast conspiracy to make us think she can speak?
She didn't speak. She cannot speak because language function is located in the left cerebral hemisphere and she does not have a left cerebral hemisphere. She doesn't have a right cerebral hemisphere either. The evidence presented at the trial is quite clear on the fact that her brain has liquified. So, as far as her speaking, the logical and scientific explanation is that air came from her lungs and in passing through her vocal cords, a vowel sound was produced. The people in the room interpreted the sound as a word.
Dead bodies (completely dead bodies) can also emit sounds when turned in such a way that air trapped in the lungs comes out. Strange but true.
I am not trying to be difficult. I am trying to make the point that Ms Schiavo is not suffering. She has only a brain stem, which controls breathing and essential bodily functions, but she does not have anything left of the part of the brain that can think, feel, sense and experience. From my point of view, this means she is dead already, but I respect other points of view that say she is still a living person. I am not knowledgeable about theology, so I have no idea whether the soul is still in a body which has no brain.
So again, for people who are worried about what Terri is experiencing: she is not suffereing; she is not in pain; does not feel herself starving to death. We on the outside are imagining what it would be like for her based on our own imagination. She lacks the "receiver," so to speak, so she cannot register what is happening to her body.