Usually in DnD/Pathfinder, Humans are considered very diverse. They have relatively short lifespans (compared to Elves/Dragons/Dwarves) and often have more than one child. So to find room to grow crops, humans sometimes leave their birthplace and go somewhere else...and over a few hundred years the language mutates until it might as well be a distinct thing.
Compare that to the Elves who have much fewer children, but also live a lot longer. It takes much longer for a language to mutate from the Elven language because even 2-3 hundred years after the group moved, there would still be living people who could speak the original language. Sure it would mutate but much slower than if a human had done the same thing.
Dwarves of course live longer than humans, if not quite so long as an elf and usually they live in extensive mining villages. I would expect that there are multiple dwarven tongues but the same thing that slows the mutation of the elven language would apply.
In the Planes of course, the various kinds of Celestial or Infernals are all effectively immortal and usually have the gift of tongues on top of that. Their language is liable to change very slowly if at all.
A dragons language. in may campaign settings has a lot to do with magic which proabbly slows the mutation of the language...plus of course the 1000+ year lifespan of dragons plays a part as well.
Of course this is just a guess, but its what I would assume plays a part.
Compare that to the Elves who have much fewer children, but also live a lot longer. It takes much longer for a language to mutate from the Elven language because even 2-3 hundred years after the group moved, there would still be living people who could speak the original language. Sure it would mutate but much slower than if a human had done the same thing.
Dwarves of course live longer than humans, if not quite so long as an elf and usually they live in extensive mining villages. I would expect that there are multiple dwarven tongues but the same thing that slows the mutation of the elven language would apply.
In the Planes of course, the various kinds of Celestial or Infernals are all effectively immortal and usually have the gift of tongues on top of that. Their language is liable to change very slowly if at all.
A dragons language. in may campaign settings has a lot to do with magic which proabbly slows the mutation of the language...plus of course the 1000+ year lifespan of dragons plays a part as well.
Of course this is just a guess, but its what I would assume plays a part.