6. The method of claim 1 , wherein the variance criteria further comprises a right-hand side variance criteria comprises a number of different characters which appear adjacent to a right-hand side of the new word candidate character string divided by the frequency of the new word candidate character string in the retrieved sentences.
6. The method of claim 1 , wherein the variance criteria further comprises a right-hand side variance criteria comprises a number of different characters which appear adjacent to a right-hand side of the new word candidate character string divided by the frequency of the new word candidate character string in the retrieved sentences. 7. The method of claim 6 , further comprising: calculating the variance criteria comprises calculating the left-hand side variance criteria and the right-hand side variance criteria; the second threshold comprises a left-hand side variance threshold and a right-hand side variance threshold; and calculating the character association criteria for only new word candidate character strings that have a left-hand side variance criteria greater than the left-hand side variance threshold and also have a right-hand side variance criteria greater than the right-hand side variance threshold.