Well, as I said there's no "common", so "Faerunean common" may actually be the language known on other worlds as European, or African, or whatever. Just pick one of the 'human languages' I listed to represent 'faerunean common', but keep in mind if there's more than one of you from FR that you'd have to agree.
Also, i like messing with stuff, so even if you ARE from a specific setting, there may be a few.. 'inconsistencies' with what's normally considered "Cannon" for a setting.
Now, i'm writing some of this as we go, incorporating your backgrounds and ideas, so here goes what i've come up with from Sin's most recent post...
[sblock=Earth History/Info]
A
long time ago, Earth humans had advanced both technology and Magic. They managed to open portals to other worlds, traveling through to explore them. One of these worlds was Faerun of the FR setting, where they were discovered by the Elves. Soon enough, the Elves were able to open portals to this world as well, and began 'stealing' the humans to popluate their own world and live as a 'work force' for the elven overlords. Soon enough, the advanced humans discovered this, and though they were unable to retrieve their people, they managed to put a stop to it by permanently shutting off planar travel FROM their world, with the exception of a few specifically designed locations where 2-way travel was possible. Shortly thereafter, all contact was lost with Earth. Nobody knows for sure, but the common theory (On worlds with history old enough to remember, and that had interacted with them, such as Faerun) is that the cessation on outgoing planar traffic stopped beings who died there from passing on as intended, and some sort of global catastrophy decimated the population. With nowhere to go, the souls became undead and soon the world was bereft of life.
A few things scholars with knowledge skills might know

I'll come up with more for those of you who actually put points into the Knowledge)
Anything that Dies on Earth stays there. Souls do not travel to other planes, respawn, etc. A lich who dies on earth with his phylactery on another plane is screwed. If the Tarrasque were to die on Earth, it would respawn on EARTH. An outsider dieing there is not banished, but permanently destroyed. Normal living beings tend to become undead within days if the body's are not destroyed.
There are rumours that many of the wonders achieved by mankind before their downfall are still hidden around the planet, as are the secrets to what actually happened. There are also a few (at least one per continent) EXIT portals, doorways that swing both ways... Though where they lead is unknown, and they are always hidden inside Guard's fortresses.
*more info coming soon*
[/sblock]
Keep in mind that the info in this Sblock is NOT common knowledge. If you think your character should be privy to it, you'll need ranks in Knowledge:Earth or Knowledge

lanes. If you think you should have some of the info even without these skills, give me the reasoning (IE ethandrew's character worked at the Processing plant, and would know SOME of the Earth info.)
As to the Language thing... Illumian I'll give a human language.(Same with other Half-human or partly human), and since they have a racial trait that says they're literate then, well, they're literate.
As for the Goliaths' body language... How about body/sign language as a racial language for Goliaths and added as a 'common' language that can be learned by any race? Also most 'basic' body language is easily readable, and I'd give Goliaths an easier reading of other body language... once the other's realize he can understand their signals.
As for the Demon... If you're willing to leave it up to me, I've got a wicked idea in mind.
And BTW, practically nothing's outside the scope of one of my games.
