Isn't the answer "two" ? "One" and "None" (or on and off) ?

Of course I see the obvious bootstrapping problem where you relate the encoding starting with just those two words but ... somehow I think that's easier to overcome than it seems ... as in, I think it must be possible.

If Helen Keller can write a book, surely I can relate digital encoding to a toddler over the course of a year or three, right ?