6. A method performed by a computer processor executing computer program instructions tangibly stored on a first computer-readable medium 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, and tangibly storing a representation of the likelihood score in a second computer-readable medium; (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 tangibly storing a representation of the relevance score in a third computer-readable medium; (C) deriving, by dividing the relevance score by the likelihood score, an emphasis factor for modifying an emphasis placed on the region of the spoken audio stream when played back, and storing a representation of the emphasis factor in a fourth computer-readable medium; and (D) modifying, in accordance with the emphasis factor, the emphasis placed on the region of the spoken audio stream by gradually decreasing the emphasis factor applied to at least one word occurring after a last word in the region of the spoken audio stream, producing an emphasis-adjusted audio stream.
6. A method performed by a computer processor executing computer program instructions tangibly stored on a first computer-readable medium 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, and tangibly storing a representation of the likelihood score in a second computer-readable medium; (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 tangibly storing a representation of the relevance score in a third computer-readable medium; (C) deriving, by dividing the relevance score by the likelihood score, an emphasis factor for modifying an emphasis placed on the region of the spoken audio stream when played back, and storing a representation of the emphasis factor in a fourth computer-readable medium; and (D) modifying, in accordance with the emphasis factor, the emphasis placed on the region of the spoken audio stream by gradually decreasing the emphasis factor applied to at least one word occurring after a last word in the region of the spoken audio stream, producing an emphasis-adjusted audio stream. 7. The method of claim 6 , wherein (C) comprises deriving, from the likelihood and the measure of relevance, a timescale adjustment factor for adjusting a playback rate of the region of the spoken audio stream.