1. A method for coding text data, comprising the steps of: generating a Hidden Markov Model which computes a probable coding responsive to a first group of text data; coding the first group of text data using a Viterbi algorithm using the Hidden Markov model; correcting the Hidden Markov Model based upon the coding of the first group of text data; and coding a second group of text data using the Viterbi algorithm using the corrected Hidden Markov Model.