“…The random variables whose joint probabilities must be estimated are letter, word, or part-of-speech labels. Linguistic context is always order-dependent, and therefore often modeled with transition frequencies in Markov Chains, Hidden Markov Models, and Markov Random Fields [16,17,18,19,20,21,22,23,24,25,26,27,28]. Linguistic variables are usually assumed to be independent of character shape, even though titles and headings in large or bold type have a different language structure than plain text.…”