[duskwuff]

Even 700k would be ridiculous; it implies that not only has the ASL population roughly doubled in the last 50 years, but also that that population is entirely incapable of reading written English. That's clearly not true.

700M is simply ludicrous. Even if that's only taken as the number of ASL signers, that would still make ASL the third largest language in the world, ahead of Hindi and Spanish.