The society of Xian draws a distinct difference between innate arcane magic and the learned variety. The latter is distinctly superior in their eyes, but it doesn't make the former any less useful. A sorcerer is born with the power of magic in her veins, and she can wield it as naturally as she breathes. No academies exist for sorcerers in Xian, but certain small circles of more experienced sorcerers do make a point of mentoring younger ones through the rough early stages of the power. After they've been taught enough good judgment to avoid burning down the marketplace, they're left to their own devices, with the expectation that they'll do the same for a young sorcerer someday.
A few sorcerers are female goblinoids, who have a predilection to the power. Most of them are smart enough to keep their talents very well hidden when outside their tribe- a goblinoid witch can expect a very brief life should she be found out by humans. Commoners tend to be uneasy about sorcerers, as with all arcane casters. Magic that comes neither from the gods nor inner strength looks all too much like the Red Tide to them.
Sorcerers may choose their known spells from the Player's Handbook, the Player's Handbook II, and the Complete Arcane. Spells from other supplements are not available unless the sorcerer finds a copy of the spell somewhere or researches it himself. Those without access to the books mentioned above should find the spell list at the online D20 SRD to be serviceable.