How does sound travel through wires?

Sound, in terms of the vibrations that we actually hear, does not travel long-distance through wires. For phone calls and such, the "sounds" are encoded as electrical signals, which then pass through the wires, to be translated into sounds at the other end.

However, actual sound could travel short distances through wires. For example, if you tap your headphone cord right now, you may or may not hear it, depending on what kind of cord and headphones you use. This is an example of actual sound, not electrical signals, passing through a wire.

It is important to realize that the sound you hear when you tap your cord does NOT come from the speakers. They can only interpret signals, and cannot amplify actual vibrations in the wire.