Lot of assumption come up with these kind of questions. Wouldn't it be nice if.....
Yes we all have ideas and hopes, I do too, but the Word says:
1Co 13:12
For now we see through a glass, darkly;7 but then face to face: now I know in part; but then shall I know even as also I am known.
We just do not see the whole picture, and some things that we cannot answer from the Word God has given us, we will not know the answer to.
I find it kinda logical that we would go back to one language , as there would npt be any more need for it all to be different, as we will not be disopbedient to God and try to match His power no more. That was the reason for God to create different languages at the tower of Babel. Yet I cannot find a clear answer to it from the Bible so I suggest it is something God has no interest in letting us know. He must have a good reasson for that. So I do not worry about it, and have stopped trying to answer the question.