3. The method of claim 2 , wherein each of the selected audible versions of stories was generated by either recording a human verbal reading or by the text-to-speech system, and wherein the references to the selected audible versions of stories are ordered in the playlist so that references to verbally read stories are interspersed with references to text-to-speech generated stories.
4. The method of claim 3 , wherein ordering the references comprises ensuring that no more than a maximum number of references to text-to-speech generated stories separate references to verbally read stories.