Re: If traveling @ the speed of sound and spoke, would you hear yourself?

Doug,
looking at your question purely "academic" the answer could be "no". Sound 
cannot move relative to the speaker (in the direction he moves!) if the 
speaker moves at the velocity of sound. However, there are several points 
to take into account:
When you hear yourself speaking, a lot (or most?) of the sound that you 
hear does not travel from your mouth to your ear via the air. It travels 
through your head ! Solid and liquid bodies can also "carry sound".
If someone travels at the speed of sound in an airplane he can understand 
himself perfectly well (apart from the noise). The velocity relative to the 
surrounding air is what counts. Imagine someone sticking his head out of an 
airplane...