Common

Amazingly, the vast array of races spread out across the dimensions all manage to communicate perfectly, using a language very similar to colloquial English.

In-story Theories of Common

• Tauroch did it
  • Premise: Tauroch, the Lord of Lies, gave mankind the Common tongue on the pretense that it would help them, but in reality it was to make it easier for Tauroch to mislead, deceive and corrupt them
  • Support: Similarities between Common, Alte Tasnikanze and Uld Tichondtha. Cyclical Gate Connection theorists hold this as a central tenet to their belief that the Gates that connect worlds appear and fade in cycles
  • Counter: Dissimilarities between Common (and Alte Tasnikanze and Uld Tichondtha) and languages like Scandish and the various Xsian dialects. Also, critics of this theory point out that most gods are capable of speaking many (if not all) mortal languages, and that if it was Tauroch himself who first instigated this theory it's possible he was lying. Anthropologists who deal with ancient languages have not been able to empirically verify this theory (perhaps because Gods aren't ones for leaving much in the archaeological record).

• "Spirit memory" theory
  • Premise: Memory is spiritual, and can be accessed through a shared spiritual memory bank. Common originated over millennia of mankind's use of this shared memory bank, well before first contact between the dimensions
  • Support: Ghosts seem to remember things, suggesting that memory is spiritual rather than physical. Also: you don't see pictures of peoples' memories when you saw open their heads and look at their brains.
  • Counter: There are plenty of skeptics ready to debunk this theory as outlandish, even for a setting in which magic and the supernatural are somewhat commonplace. Those who frequently work in realms of the mind (wizards and psionicists) do not believe this is true. The neurological sciences seem to suggest exactly the opposite, as numerous brain damage cases (which often affect memory) seem to suggest that memory is, in fact, physical. Also, the laws in some countries say you aren't allowed to saw open peoples' heads, even if it is to see if you can see pictures of their memories.

• Parallel Evolutionary theory
  • Premise: A powerful force in the anthropological sciences, Parallel Evolution holds that similar species evolved on different worlds parallel to each other, and as a cultural component to this theory, it also holds that Common evolved differently on different worlds.
  • Support: The lack of empirical evidence to prove otherwise, mainly. There is charted evidence that Parallel Evolutionary linguists have uncovered in various dimensions which shows very plainly several distinct linguistic evolutions toward the development of the Common language.
  • Counter: Cyclical Gate Connection theorists point to their own linguistic evidence (the similarities between Common, Uld Tichondtha and Alte Taznikanze) as sufficient refutation of Parallel Evolutionary linguistics. Other critics of Parallel Evolution point out that the core of the support they offer for their theory seems to boil down to "well, the opposite isn't empirically provable, therefore..."

• Intra-Web Supermigration theory
  • Premise: A school of anthropological thought fiercely opposed to Parallel Evolutionism, the Supermigrationists oppose the Parallel theory of language development entirely on principle. Their core belief is that each race has a point of origin in the Web of Worlds, and that places where similar races are found must be attributable to migration throughout the Web of Worlds. This must, therefore, hold true of language as well, though they do not attribute it to any specific deity (or any deity at all).
  • Support: Supermigrationists often recycle evidence used by Cyclical Gate theorists, because their ideas are bound to each other. But Cyclical Gate theorists tend to rely heavily on the intervention of Gods in the formulation of their explanations for the way things are, while Supermigrationists seek to keep their work strictly scientific. Supermigrationists have developed a linguistic chart that traces key points of the development of Common throughout the Web, and claims that the pieces of the puzzle only fit together if you assume supermigration between the dimensions was possible in antiquity.
  • Counter: As always, Supermigration theory falls apart in the face of there being no evidence of ancient capability for space travel, and no concrete evidence of contact between ancient Core peoples and ancient Fringe peoples, except that whole bit about the myriad similarities between Fringe cultures and Core cultures.

• "A Wizard Did It" theory
  • Premise: A Wizard Did It.
  • Support: One time, I saw this one guy, I think he was a wizard, and he created Common. He totally did it.
  • Counter: Dude, that was me, and I was taking out my recyclables.