'Probability that position j in ``trg_sentence`` is aligned to
position i in the ``src_sentence``'

def prob_alignment_point(self, i, j, src_sentence, trg_sentence):

    l = (len(src_sentence) - 1)
    m = (len(trg_sentence) - 1)
    s = src_sentence[i]
    t = trg_sentence[j]
    return (self.translation_table[t][s] * self.alignment_table[i][j][l][m])
