  Sound waves in and dielectric liquid, that consists of subsystems of valency
electrons with effective mass and ions which interact through the long-wave
potential electric field are considered, on analogies with and metallic liquid,
but with the requirement, that electric current is absent. It is shown that
usual description of sound wave in an ideal liquid as wave of mass density and
mass velocity follows from the offered consideration. It is also shown that
sound waves with other side can be considered as waves of potential electric
field in an environment. Introduction of phonons in both cases is considered.
