OK,so we all know about the dragon aspect shout. I've been thinking about that because of the line "the power only a true dragonborn can wield". Now that fact that he very specifically states dragonborn makes it obvious that this is a shout only a dovahkiin can use. Now I think that the shout directly taps into a dovahkiins life force to make him stronger,by using the energy from the animus of his soul (all shouts are powered by this,the users life force. That's why draugr shouts are weak,and the dovahkiins is so absurdly strong.) I've also been connecting it to when martin becomes the spectral dragon at the end of Oblivion,and I'm thinking this may be the same thing in action,him using his life force PLUS the life force of all the dragon souls in the amulet of kings, and could've easily expended himself or sacrificed his life essence to power it. I believe the dovahkiin can use this shout to directly tap into his dragon souls and the over soul of akatosh,using the shout so he doesn't completely expend his own life force. Also, the shout has a once a day cool day,which makes the shout unique,and might suggest that it tires out the dovahkiin.
This is something I've been thinking about for a few days,how plausible do you think it is?