Have you had this experience or has a loved one or a friend mentioned that they can hear but not understand what others are saying to them? Most often, hearing loss affects the high frequency sounds a person hears.
As a result, patients can have difficulty clearly understanding what other people are saying. Often patients can hear vowels just fine, but consonant sounds of F, S, T, and X are difficult to hear. Additionally, sounds like a woman's or child's voice, or a bird chirping are often lost. Losing hearing in those frequencies means that those sounds are softer and unclear.
Imagine removing all the high keys on a piano and asking someone to play a well-known melody. Even with only six or seven keys missing, the melody might be difficult to recognize. People with hearing loss experience a similar variation of the soundtrack of their lives every day.