Complex sentence: Therefore the speed of light and all other propagating effects are determined by the physical properties of the aether at the relevant location, analogous to the way that gaseous, liquid and solid media affect the propagation of sound waves.
Split into simpler sentences: Therefore the speed of light and all other propagating effects are determined by the physical properties of the aether at the relevant location. This is analogous to the way that gaseous, liquid and solid media affect the propagation of sound waves.