Dude, I think you should forget about it. Unless you're prepared to create it yourself, of course.
Isn't the whole point of Skyrim that the Dovahkin is the only one who can use shouting without years of Greybeard training?
- and who would want one of those depressing old hippies as a companion anyway?
Also, AFAIK, Illia doesn't use shouts, just destruction magic.
The dovahkin is so important because of what needs to do to learn shouts, absorb the souls of dragons that otherwise would be raised again.
All skills are supposed to need years of training. The same can be applied to thu'um. It's totally lorefriendly to have followers learning as much shouts as possible, the same way it's lorefriendly for them to learn conjuration or alchemy.