I don't think the phonemes have been ported to the new face rig. It was a while, but I'm pretty sure the last time they were implemented as shape keys rather than via rigging.
However, there's still a phonemes/visemes thingy in MHX2 I think. Maybe it'd be worth checking if there's something there that could be reused.
If not, providing a phoneme pose library would be a good deed.
