Genesis 11:1-4

Genesis 11:1-4 show that everyone had descended from eight people and that they had stayed together makes it logical that their language would be the same. The land of Shinar was roughly part of modern-day Iraq and this reference shows familiarity with the area since dried or fire burnt bricks are the most practical building material in that part of the world. This is actually supported by DNA Evidence. (see reference)\

Reference

DNA and Babel and human migration