I've always been slightly confused by this. Anyone who isn't a dragon that can shout is a Nord. Ulfric stated that, "Any Nord can learn the Voice, should he train hard enough," Or something of the like. The Greybeards are Nords. The Dovahkiin is also strongly hinted to be a Nord. Tiber Septim was a Nord (most likely). The Draugr are Nords. Felldir, Gormlaith, and Hakon are all Nords. So I'm just wondering, is it like, impossible for other races to learn it, mainly the elven races? I understand the player can be any race they want, but that's for obvious reasons.

So am I missing something, or is their actually truth behind the speculation?

Anyone can learn the Thu'um, it's just a form of magic that is harder to master. For instance there are other thu'um-like magics in TES one being in akavir.

Anyone can shout, not just Nords. Case in point:

Is there anything he can't do?

That isn't true. The CoC isn't by default an Imperial, or the Nerevarine a Dunmer. Their races and details are unknown and lost to time. It is all how we chose to play that decide the race of our heros.

Well, you're in Skyrim. Why would they tell you about anybody else other than a Nord shouting? That's like American high schools teaching you about good communists. Besides, the thu'um comes from dragons, which ruled over mostly Skyrim. So it makes sense that the skill is contained within that region.