The Common Tongue

[Citizen West]

So, Westeros has been subject to numerous migrations and foreign conquests over the centuries. Until very recently, independent kingdoms that have their own unique religions, customs and identities stretching back before recorded history. For the most they don't really trade much, and there are tons of natural boundaries everywhere so there's not much overlap between different groups, like say the North and the Riverlands or Dorne and the Reach.

Yet somehow all these different people speak the exact same language? How does that work?

[RumHam]

So, Westeros has been subject to numerous migrations and foreign conquests over the centuries. Until very recently, independent kingdoms that have their own unique religions, customs and identities stretching back before recorded history. For the most they don't really trade much, and there are tons of natural boundaries everywhere so there's not much overlap between different groups, like say the North and the Riverlands or Dorne and the Reach.

Yet somehow all these different people speak the exact same language? How does that work?

A wizard did it.

I think it's just something Martin decided on to make the story easier to read, and save himself from having to come up with a dozen different languages. I think the in-universe explanation is that the Andals brought the common tongue to Westeros and the northerners eventually adopted it as well.

[The hairy bear]

Yeah, it's one of the things that are like this just because the author wants it. IMO, harder to swallow than the weird seasons or the fire-breathing dragons.

Even if the Andals had brought a single tongue, even if the maesters acted as a unifying force, and even if the Targaryens forced cultural homogenization in their kingdom, it wouldn't be believable.

[Ancalagon the Black]

Yeah, 5-6000 years is more than enough for natural drift to form new languages, for example Dorne is relatively isolated and really should have developed their own language. Not to mention, the Invasion by the Rhoynar and the large effect they had on Dornish culture apparently had no effect on the language. Martin just hand-waved it, which I suppose is fair enough, the story doesn't really need it - it's enjoyable enough.

Come to think of it, why does the North share the same language if the language was bought by the Andals? They have only been part of the Kingdom for 300 years, and there have been no laws necessitating speaking the Common Tongue there like Britain with Wales.

[MercyTheBlindUglyLittleCat]

I could be wrong, but i never assumed they all spoke the EXACT same language in the Seven Kingdoms until Aegon unified them. From their 300 years of a unified royal language centered around trade and politics in KL can be plausible. Though I'd have to think that in order for that to make sense, the Andal language couldn't have drifted too far from its roots. I think that could relate to the pre-AL timeline and history being overly extended and inaccurate. The Andal arrival and spread may not have been so long ago. The reasons why the Targs didn't make High Valyrian the official language I feel have been explained. Also, the Maesters all being trained in Old Town is probably a help. The Lords and Kings of Westeros have all been educated from the same school.

[Oren]

If the Andals brought the common tongue and the North adopted it, then they should have been speaking a different language north of the wall. Although, it is possible that the wildlings migrated north to the wall, after the long night ended, and they were originally northerners. Mostl likely, however, this was overlooked by GRRM.