Languages same as base race.
Tieflings are the descendants of demons or devils who consorted with mortals. This cursed heritage leaves them with a stigma they carry from birth until death. They are typically easy to identify by fantastical physical characteristics such as horns, tails, and cloven feet. Some are lucky enough to have more subtle traits such as oddly colored eyes or claw-like nails.
People tend to assume the worst of a tiefling which generally has two results: either the tiefling falls into the stereotype of evil, or they do everything in their power to prove themselves better than their demonic predecessors.