To understand words it is necessary to hear all the speech sounds, transmit them to the brain, and decode the meaning. If anything disrupts this sequence it is likely that you will hear but not understand. The most common disruption is inability to hear certain sounds. It will appear that your hearing is fine but in reality you are missing critical sounds for understanding. Another common problem is loss of word discrimination in the brain. Proper amplification will maximize your ability to hear and understand in most situations.