15. The computer program product of claim 14 , wherein the determining the best candidate solution comprises comparing the spelling errors with all words in a dictionary using the variable Damerau-Levenshtein cost distance and selecting one or more words having a minimum variable Damerau-Levenshtein cost distance.
15. The computer program product of claim 14 , wherein the determining the best candidate solution comprises comparing the spelling errors with all words in a dictionary using the variable Damerau-Levenshtein cost distance and selecting one or more words having a minimum variable Damerau-Levenshtein cost distance. 16. The computer program product of claim 15 , wherein the determining the best candidate solution further comprises: choosing a sequence of letters with a maximum marginal probability via the A* lattice search and the m-grams probability estimation, wherein: the A* lattice search follows a best-first path strategy to select a path through a best candidate trellis; the best-first path strategy is a statistical score of a path until its terminal expansion node; and a heuristic score function is added to the best-first path strategy to expand during the A* lattice search, wherein, the heuristic score function stays above a minimum upper bound of a probability estimation.