Why does Everyone Speak Common?

I’ve been designing my own dungeon, one of those archetypal dungeons right under a town that connects to a graveyard and has an underground river. The people in the town are nice enough but for some unknown reason the gods cannot bear to look at the town. This town exists completely cut off from the rest of the world and from the gods.

I started wondering what language they would speak. I had an idea to make it that few people in the town spoke common. And when you went in the dungeon the writing you found down there was unintelligible; but as you went farther down in the dungeon the writing became more and more intelligible. At the final level of the dungeon, the oldest, everything was written in common.

 The idea was that common has been around for a very long time, was perhaps the oldest language, created by the gods. The people of the town developed their own language because they had been separated from the gods for so long. The town’s name (fore example) is unpronounceable not because it was old but because it was new. I decided against this. I was afraid it would have too many unforeseen consequences and I would screw it up and my players would laugh at me.

It also meant that I have to come up with a lot more stuff for the lower levels of the dungeon in terms of what is written on the walls what the scrolls say etc.

I ditched the idea.

Then I started wondering about where common comes from and if anyone had spent any semi-serious thought on what the implications would be if the whole world spoke one language. How could that be possible especially in the anarchic prototypical dungeons and dragons world? There is not government and no public education regulating speech. How could it be that everyone speaks pretty much the same language? I wondered if there was a better approach than ignoring this aspect of the game. Googling turned up nothing. Apparently no one cares, which make sense, I mean no one I’ve played with has every said, “hey how come everyone speaks the same language even though there are no cultural or social forces that would prevent language from splintering into a bunch of different dialects?”  

So, I started thinking about it.

If language is staying the same everywhere over time there must be some force controlling the language and if the ancient languages down in the dungeon are different then this force must not have existed in the past or behaved differently in the past. Since my town with its unpronounceable name was exempt from this force that meant it probably had something to do with the gods. I came up with this:

The gods have an interest in creating a common language for humanity in order to unite and control it. The gods also have an interest in it being hard to read old writings. Older writings contain blasphemies and secret knowledge. They describe a time before the current gods had consolidated their power and brought order to the world. The gods prevent the language from changing because the gods that currently control the world are lawful and allowing chaos and entropy to enter the language reduces their control.

This doesn’t really add anything to the game until higher levels when players might amass enough forbidden knowledge to make the gods come after them. It does explain why sages would charge a lot, they are risking divine wrath whenever they share knowledge. It also goes towards explaining why wizards would build their towers so far out of the way; it draws less attention. What the gods fear is widespread dissemination of knowledge.

It also might explain why you need the read magic spell to read magic.  The gods have created a language that constrains the human mind. The read magic spell allows the magic user to break the constraints of the god-created common language and understand the older more expressive/powerful language of magic.