You listen with your brain and your ears. Your brain makes meaning out of all the clues available. When you are listening sounds are an important clue. But you also need to make use of your knowledge.Your ears pick up sounds; your brain makes the meanings.
The two main parts of the listening process are:
and
This means making as much use as you can of the low level clues. You start by listening for the individual sounds and then join these sounds together to make syllables and words. These words are then combined together to form phrases, clauses and sentences. Finally the sentences combine tgether to form texts or conversations.
Top-down listening means making as much use as you can of your knowledge and the situation. From your knowledge of situations, contexts, texts, conversations, phrases and sentences, you can understand what you hear.
Of course, good listeners need to make use of the interaction between both types of listening. For example, if you hear the sound /ðɛə/, it is only the context that will tell you if the word is "there", "their" or perhaps "they're". Your knowledge of grammar will tell you if /kæts/ is "cats" or "cat's", which may be "cat is" or "cat has".