What is sound energy?
Sound energy is simply the vibration of molecules.
Energy from a speaker travels from one molecule to another. The molecule vibrates and in turn causes neighboring molecules to vibrate as well. They all vibrate back and forth, transferring the energy.
You can produce sound energy in various ways. Most commonly you hit an object against another. Your motion provides kinetic energy and as it hits something, some of the energy becomes heat energy, kinetic energy and sound energy. As long as the object vibrates, sound is produced both inside the object and outside (air).
Put your ear against the table and tap the table. You are hearing the sound from the solid itself.
If there is some work being invested to vibrate matter molecules, you will have sound.