12. The computer-readable storage device of claim 11 , wherein the set of ordered lists of speech units are further ordered by speech unit pitch.
12. The computer-readable storage device of claim 11 , wherein the set of ordered lists of speech units are further ordered by speech unit pitch. 13. The computer-readable storage device of claim 12 , wherein speech unit pitch is a dominant one of multiple factors by which the lists of speech units are ordered.