4. The method according to claim 1 , further comprising: identifying bigrams that are entirely composed of meaningless unigrams; determining whether the identified bigrams are individually meaningless; and assigning at least a portion of the bigrams identified as being individually meaningless to the first n-gram class.
6. The method according to claim 4 , further comprising: identifying trigrams that are entirely composed of meaningless bigrams; determining whether the identified trigrams are individually meaningless; and assigning at least a portion of the trigrams identified as being individually meaningless to the first n-gram class.