She can read thanks to signing?

I'm sure many of you saw this on tv or read about it last spring. A 17 month old girl could read:

NBC's TODAY show

From the show:

when Elizabeth was born,...they started teaching her sign language along with spoken language. They read to her often, and her favorite television program — the only one her parents let her watch — was a PBS show called “Signing Times,” which teaches kids sign language.
...
“We tried to do everything we could to try to stimulate her language growth,” Michael Barrett told Curry. “From day one Katy has been using sign language with her. We think anything relating to language is a good thing to nurture.”

I agree! I think that all babies/children should be exposed to several languages at as early an age as possible.

Obviously, this 17 month old girl is special but did the word association between speaking, watching, and signing help her to read so early?

- Lori

Edited to add additional information from Rachel from Signing Time:
http://www.signingtime.com/rachel/2008/11/07/meet-elizabeth/