Infernal

Infernal is the language of devils. Tieflings are naturally able to speak, read, and write infernal. Although not inherently evil, the language is often used in the underground and those who speak it are often looked down on.
The written language consists of a runic alphabet much like Draconic and Dwarven. However, there is a stigma against the text and anything written in Infernal is usually assumed to be a curse, dark magic, or a demonic summoning.