Mr. Brown says that ,,spoken language does indeed contain a good deal of redundancy, it also has many reduced forms…” That is why (in my opinion) is listening more difficult. Person who is on the elementary or intermediate level is not able to understand reduced forms in the stream of sounds (speech) like I’ll /ail/, you’d /youd/ etc. He does not understand what does “ail” mean. He knows only “I will”. But when speaker say ,,I will” not “I’ll” there is no mistake.
Another example why speaking is not the most difficult (while listening is) is because of ,,the rephrasings, repetitions, elaborations and little insertions of ´I mean´ and ´you know´ etc.” (Brown). This means that using of these “empty” phrases is not obligatory for the speaker. Of course the speech is more natural by using these phrases. On the other hand, these “empty” phrases may cause to listener-beginner some problems in understanding