1. A method performed by a computer processor executing computer program instructions tangibly stored on a first computer-readable medium, the method comprising steps of: (A) tangibly storing, on a second computer-readable medium, a data structure representing a plurality of editing patterns of the form T=(D,E,C), wherein each of the plurality of editing patterns relates particular content D in an original document corpus to corresponding content E in an edited document corpus in a context C shared by contents D and E, wherein the original document corpus and the edited document corpus are tangibly stored on a third and fourth computer-readable medium, respectively; (B) deriving a plurality of correction rules, tangibly stored on a fifth computer-readable medium, from the plurality of editing patterns; and (C) deriving a classifier, tangibly stored on a sixth computer-readable medium, for particular content D based on the data structure representing the plurality of editing patterns, the classifier defining decision criteria for selecting one of the plurality of correction rules to apply to content D based on a context C* of content D.