Extensive Listening (EL) is a way to improve your listening fluency. But what is listening fluency? When you learn a language, there are two things you need to do. The best way to do this is to read or listen to language which you understand. If you understand almost all of the text you listen to, you can build your word recognition speed, you’ll notice more uses of grammar points, more collocations and generally your brain will be working very effectively. The listening, provided it is done at the correct level, will also help improve automatic processing of language (immediate and fluency processing) which allows your working memory to concentrate on comprehending what you are listening to.
So, building fluency means building your listening speed. This means being able to understand almost everything you are listening to at the level you are listening. A beginner level student would listen to something with very few unknown words and the simplest of grammar. An intermediate level listener would choose a listening text that had a wider range of vocabulary and grammar, but, importantly it is still quite easy. So the important point here is that ‘difficulty’ is NOT a property of a text, but of the listener. A given text may be easy for one person, but the same text may not be easy for another. Therefore one’s ability level decides whether a given listening text is easy or not.