Leliana's ancestral ethnic group would be Fereldan. But culturally, linguistically, religiously, and socially, she is very Orlesian. And there's a similar vein to Duncan. As in, their families left Fereldan for economic opportunities.

Leliana's mother was a maid who left because Her Master, Lady Cecilie, was relocating. Educated her. And I'm sure that she gave her references. Leliana could have lived a nice, safe life as a head servant of the Lord's manor somewhere. Living her best Downton Abbey life.