Seems like a fun hardware hack, but if he wants his niece to be able to communicate effectively he should probably just learn frickin sign language. It's unlikely that these can read a vocabulary, just the alphabet, which is incredibly limiting.
So, cool, looks like fun to hack on, almost certainly not newsworthy.
There's a long history of folks trying "something new" in the accessibility space and discovering that if they'd have talked to the people with impairments they're trying to help that there are significant problems with the approach.
As you can imagine, this external savior thing can be pretty frustrating to the people who actually live their lives with a particular impairment.
So, cool, looks like fun to hack on, almost certainly not newsworthy.