That is a popular request but it requires a lot of efforts from me, so I don't know when this will be added.
Right now I recomend you to select more simple audiobooks.
To study English there are abridged books series: "Oxford Bookworms", "Penguin Readers", "Cambridge Readers", "Macmillan Readers".
They have been read very slow, with pauses and using simple words.
Check this page: Where to get audiobooks