So, long before my wife Claudia and I had our son, Rupert, 16 months ago, we’d already discussed the importance of bringing him up with both speech and sign language from birth. And that’s exactly ...

An appreciation for language was instilled in William Cashore by his parents at an early age. His mother was an elementary school teacher and would quiz him on words in between homework assignments.

There are more than 70 million people who use sign language around the world, and as the world remembers the importance of ...