Sound vibrations from the air enter the earacanal, strike the ear drum. This starts vibrating the tiny bones attached to the eardrum. This vibration is passed on to the fluid in the inner ear called cochlea. Within the fluid are immersed hair like cells, which when vibrate, do the magic. They convert the air vibrations into electric patterns, which goes to the hearing part of the brain through the hearing nerves. Brain’s hearing part correlates the pattern with the language and memory part. That’s how we understand the meaning of the sounds.