When interacting, people often "wait to speak" rather than listening attentively. They might also be distracted. Active listening is a structured way of listening and responding to others, focusing attention on the "function" of communicating objectively as opposed to focusing on "forms", passive expression or subjectivity.
There are many opinions on what is "active listening". A search of the term reveals interpretations of the "activity" as including "interpreting body language" or focusing on something other than or in addition to words. Successful communication is the establishment of common ground between two people—understanding. Agreeing to disagree is common ground. Common ground can be false, i.e., a person says they feel a certain way but they do not. Nevertheless it is common ground, once accepted as understood. Dialogue, understanding and progress can only arise from that common ground. And that common ground cannot be established without respect for the words as spoken by the speaker, for whatever reason.
Thus the essence of active listening is as simple as it is effective: paraphrasing the speakers words back to them as a question. There is little room for assumption or interpretation. It is functional, mechanical and leaves little doubt as to what is meant by what is said. "The process is successful if the person receiving the information gives feedback which shows understanding for meaning. Suspending one's own frame of reference, suspending judgment and avoiding other internal mental activities are important to fully attend to the speaker.