Spasmodic Dysphonia

Weird. Apparently Scott Adams (creator of the Dilbert comic) lost his voice about 18 months ago as a result of a very strange and exotic disease called Spasmodic Dysphonia-- where the part of the brain that controls speech just fritzes out. People with SD can't speak normally, but can often sing or chant or (in weirder cases) talk if they pinch their noses or speak in a falsetto or other "fake" voice.

This is usually permament, but Scott apparently has recovered his voice (at least partially) in the last week or so; he's one of the few who has ever recovered from this.

You can read his experience here, in his blog.