It's the gift that keeps on giving all year long.
Simply put our ears hear sounds, however it is the brain that interputes these, in which one is able to understand.
Hearing loss exists when there is diminished sensitivity to the sounds normally heard. The terms hearing impairment or hard of hearing are usually reserved for people who have relative insensitivity to sound in the speech frequencies. The severity of a hearing loss is categorized according to the increase in volume above the usual level necessary before the listener can detect it.