[RPG] Overview of common languages per plane


For my current campaign I'm exploring lore options regarding planar travel for NPCs and PCs. Where in the books can I find more information about which languages are common in which planes?*

I'm aware that the Monster Manual states which languages a creature knows and/or understands. But the details don't offer me demographics on how common certain languages are. Or am I missing something in the book?

*My campaign takes place in a personal adaptation on the planes of the Forgotten Realms.

Best Answer

PHB 123 and DMG 43

The information on PHB 123, is similar to that on MM. Together with the information on DMG you can have your answer.

PHB shows which languages are spoken by which type of creatures. DMG talks about creating, or putting together, planes. The common language would depend on whose plane it is.

For example if the plane in question is the origin of Demons the common language there would be Abyssal. Or Celestial for the dieties, Sylvan for fey creatures etc.