Yoke of Stars - R B Lemberg - Bog

"In the School of Assassins, Stone Orphan waits for a first assignment. After their first kill, they will graduate and attain the coveted cloth of bone. But instead of a commission, Stone Orphan gets an inquisitive linguist, Ulâin. Ulâin has heard the Orphan Star's song of despair, mirroring her own, and drawing her to the School of Assassins. But Ulâin is far more interested in learning Stone Orphan's language than deciding whom she wishes to kill"--