"Genesis chapter 10 presents what is commonly known as the “Table of the Nations.” It lists 70 families or nations descending from Noah’s sons, giving some indication of where these eventually spread to and settled. Of course, Moses recorded this centuries after the Flood and the confusion of languages at Babel. So he was in position to bring together in what is now Genesis chapter 10 details of how things worked out over the centuries.
"After Genesis chapter 10 gives the details of the “Table of the Nations,” chapter 11 takes up the narrative or chronological history with Babel and shows how it was that many languages came about and why peoples spread over the globe.—Gen. 11:1-9.
"Thus the references in the 10th chapter to various languages are not to be understood as meaning that these developed prior to the confusion of languages at Babel. (Gen. 10:5, 20, 31, 32) But those tongues were later found among Noah’s descendants, whose lineage is provided in that chapter." - Questions from Readers, 7/15/78 Watchtower (Emphasis mine)
When was Ba'bel built and what became of Nimrod after that? (Search For Bible Truths)
What Language did Adam and Eve Speak? (Search For Bible Truths)