reply to post by PopeyeFAFL
Well, to take a stab at your question. We would see very slight dialects arise within decades of the one language. Assuming people all over the
world have preserved their history, culture, etc., it would not take too long at all for slight dialects to arise to account for peoples different
experiences, cultures, religions, etc.
The rate at which this would occur might be slower due to the rapid and prolific means of communication today. It took the U.S. about a century to
develop its own brand of English away from the British version. It may take longer now.
It would probably still take centuries for full blown differing languages to arise. It took about a thousand years for the romance languages to arise
from Latin.
Of course all this assumes we can agree on what a different language is. Often times this is a political question, and not scientific. For example
"Norwegian" and "Danish" are, for all practical purposes, the same language, but due to intense national pride, the nations of these two groups
have chosen to call them different.