What makes sound energy?

Sound is only the transference of energy via vibration of the molecules in the transmitting medium.

Ie sound in air is the air molecules being vibrated by a stimulus say a load speaker or your vocal cords.

We hear sound by receiving the vibrations on our ear drums which is converted in the inner ear into electricity which our brains interpret as noise.

Our own voices sound different to us when recorded and played back, as most of what we hear of our own voice is from vibration through the bones in your jaw and skull, which transmit at different speeds and therefore frequencies.