What language did the Shang dynasty first use to occupy servants? Please comment.

Characters used in Shang Dynasty: Wen Tao, Oracle Bone Inscriptions and Jinwen.

Wen Tao:

Oracle Bone Inscriptions: Oracle Bone Inscriptions is a kind of divination record, which is divided into many different categories, including war, hunting and sacrifice. In addition, they also offer sacrifices to wind, water, mountains, the sun and gods, which are rich in content.

Bronze inscription: engraved on bronze wares.