Unexpected Origin
Any Amaryllite or Leannite priest will tell you that love is a nebulous and powerful thing that knows no boundaries and will be held by no walls. Dragonborn are the living incarnation of this mentality. Sometimes, a True Dragon, usually a Metallic but not always, will feel the need to roam the world, and take on the form of another race to fit in. This Polymorphing ability seems to be quite rare and largely exclusive to Metallics, though Silver Queen Dragonlings have also been observed to occasionally learn to do so. And of course, sometimes love takes its course. This is a rare occurrence due to the difference in age and cultures between the two races.
General Description:
The offspring of a Dragon and an individual of another race, Dragonborn are possibly the rarest sentient race on Orth besides maybe Dwarves or Rockfolk. Dragonborn largely resemble their non-Draconic parent race; so for example, a High Elven Dragonborn will look like a High Elf. However, they usually have eyes resembling the eyes of their Draconic parent. They will also often grow scales on their back, arms and legs as they grow older, sometimes growing up their neck and across their cheeks. A Dragonborn will also usually be physically far stronger than their non-Draconic parent race, and have the breath weapon of their Draconic parent.
Secret Existence
Dragonborn tend to try and do their best to keep their identity as such a secret, out of fear of scaring others or being captured and dissected by over-enthusiastic dracologists - the latter being an event which has occurred more than once in the less civilised areas of Orth.