In most cases, you can hear people talking, but have difficulty understanding what they're saying. Perhaps you can understand just fine in quiet environments, but have trouble in noisy surroundings or in groups.
Hearing isn’t only about loudness or decibel level. Typically, hearing loss has more to do with the frequency of the sound—that is, its pitch—than its loudness. When hearing loss occurs, it’s harder to hear higher pitches—especially when there is background noise to complicate the picture, such as conversation in a noisy restaurant.
That’s why amplifying incoming sounds alone isn’t as effective in treating hearing loss as amplifying selectively. Making all sounds louder just makes understanding harder. Hearing aids are designed to amplify the specific frequencies you need for better understanding.