17. The computer program product of claim 16 , wherein the hierarchical word lattice comprises nodes corresponding to the one or more words of the first transcription of the utterance and words of the second transcription of the utterance, and edges between the nodes that identify possible paths through the word lattice, wherein each path has an associated probability of being correct.
16. The computer program product of claim 15 , wherein the one or more words are selected from a hierarchical word lattice.