So I was talking to Ryari the other day about elements and bending, and came across this notion: if, as Bryke states, bending is defined by your environment and your nation's spirituality, is there a possibility to bend more than one element?

Now, some clarifications.
—— 1. I am not talking about 'avatar' status here. Just an additional element.
—— 2. I am not talking about non-benders suddenly acquiring the ability to bend.
—— 3. I am not talking about non-Masters.
—— 4. I am not talking about off-shoot bending.

The way I see it, I think that if your background is a mixed "element" (for example, Water x Fire), the possibility of you having either Water OR Fire is about 50/50. If you're already a bender, by definition you qualify under the whole 'spirituality' thing. If you parents are equally diligent in teaching you the traditions of their culture, what's preventing you from tapping into what one can only presume is an innate affinity to the other element? Obviously, I don't think that this is something a regular joe can pick up. But, I think, through the right training, it's definitely possible.

Another point of discussion, also, is Iroh. Iroh is, as far as we've seen, the only person to incorporate every bending technique (earth, water, fire, air) into some aspect of his firebending. Iroh also has an obviously deep link into the spirit world. Since Iroh has taken to heart each nation's teachings, and considering his high affinity for the Spirit World, do you think it's possible for Iroh to be able to bend at least one more element in his lifetime?