Board Thread:Lore Discussion/@comment-46.208.244.194-20131228112337/@comment-9421524-20131228152021

I would say it's more to do with how the words are learned. The Dragonborn can use a shout right after learning it if he/she has the soul to put power into it, but the GBs meditate for years, so can probably just use it. They also know shouts the Dragonborn doesn't, like the ethereal clonse once you get Fus and Ro.