My students often complain to me that native English speakers speak too fast. They say that movies and TV shows seem too difficult to understand, and this causes them to get discouraged.
The truth is, native speakers can be difficult to understand, however, this is NOT just because of speed.
Even more than speaking quickly, the reason why native English speakers seem difficult to understand is that they change and transform their pronunciation of words and sentences.
This transformation of sounds means that there is a huge difference between classroom or written English and the real English that native speakers speak in everyday life.