Rather than classifying each phrase pair with either monotonous (M ), swap (S) or discontinuous (D), a probability distribution for the orientations is calculated.
for the previous word, given a weighted alignment matrix W , the phrase pair between the indexes i and j in S, S j i , and n and m in T , T m n , the probability values for each orientation are given by: The problem with the word-based lexicalized reordering model is that it is assumed that the adjacent words are translated by themselves, which is not always true in phrase-based SMT.