14. The method of claim 13 wherein performing an initialization comprises: expanding “that” patterns; arranging “that” patterns alphabetically; assigning a specificity rank to each “that” pattern; and adding each “that” pattern to a “that” trie.
15. The method of claim 14 wherein performing an initialization comprises: expanding megacategories into conjunctions; ordering the conjunctions alphabetically; and adding each megacategory to a megacategory trie.