Just like light waves sound waves can be reflected, refracted and diffracted.
Sound waves reflect when they hit a large object like a wall. They bounce back and can be heard as echoes.
Sound waves can be refracted when they emeter a different medium. This causes them to bend slightly. When sound waves enter a denser material, they travel faster hence making the angle of refraction greater than the angle of incidence.
Sound waves can be diffracted when the pass a doorway or there as an obstacle in their way. They bend, enabling us to hear sound waves even if there is an obstacle between us and the sound source.