28. An apparatus comprising a computer-readable medium tangibly storing instructions executable by a computer processor to perform a method comprising: (A) deriving, from a region of a document and a corresponding region of a spoken audio stream, a likelihood score representing a likelihood that the region of the document correctly represents content in the corresponding region of the spoken audio stream; (B) selecting a relevance score representing a measure of relevance of the region of the spoken audio stream, the measure of relevance representing a measure of importance that the region of the spoken audio stream be brought to the attention of a human proofreader; and (C) deriving, by dividing the relevance score by the likelihood score, an emphasis factor for modifying emphasis placed on the region of the spoken audio stream when played back.
28. An apparatus comprising a computer-readable medium tangibly storing instructions executable by a computer processor to perform a method comprising: (A) deriving, from a region of a document and a corresponding region of a spoken audio stream, a likelihood score representing a likelihood that the region of the document correctly represents content in the corresponding region of the spoken audio stream; (B) selecting a relevance score representing a measure of relevance of the region of the spoken audio stream, the measure of relevance representing a measure of importance that the region of the spoken audio stream be brought to the attention of a human proofreader; and (C) deriving, by dividing the relevance score by the likelihood score, an emphasis factor for modifying emphasis placed on the region of the spoken audio stream when played back. 31. The apparatus of claim 28 , wherein (C) comprises deriving, from the likelihood and the measure of relevance, a timescale adjustment factor for adjusting a playback rate of the audio stream.