An example of passive listening is when someone is talking to another, but the other person is only hearing the words as background noise and not particularly involving himself in the listening process. Unlike active listening, which may include focusing on the speaker's words in order to understand them, passive listening is essentially just hearing.
Passive and active listening play an important role in communication, as well as in learning other languages. If a person listens actively, he learns languages more easily because he can look for words he already knows and pick out ones that he needs to look up. Passive listeners do not learn language as quickly, because they tune out the meaning of the words being spoken and allow themselves to think of other things while listening to the language being spoken.
To avoid being a passive listener, practice active listening techniques daily. Look at the person speaking, and maintain eye contact. Ask questions if what is being said is not understood, and repeat the information back if it helps to understand it better. Use empathy when listening, and only use appropriate facial movements and gestures, such as nodding in agreement or shaking the head to disagree.