As the left/right orientations only consider whether the current source phrase is on the left of the previous source phrase or not, unaligned source words will not change orientations.
for example, both figure 2 using left/right orientations in the neural reordering model not only has a higher classification accuracy (85%) over using the M/S/D orientations (69%), but also achieves higher BLEU scores on all NIST datasets systematically.