Tolkien and Isolationism

[Galadriel55]

Originally Posted by Boromir88

So there would appear to be consequences for being expansionists, as well. Perhaps Tolkien was cautioning about being on the extremes of either end?

Well, yes. Don't be exclusive, but don't force your way onto others, let's just all be friends. A balance that is easier said than done in a real life scenario.

'Well do I understand your speech,' he answered in the same language; 'yet few strangers do so. Why then do you not speak in the Common Tongue, as is the custom in the West, if you wish to be answered?' -TTT, The King of the Golden Hall

...But how long would Rohan and Dunland and all the various other ethnic pockets maintain their own languages that are separate from the Common Speech after Aragorn's globalization? Assuming that the globalization continues after his death and the North and South don't fall apart again, that is.