Midrasch zu Bereschit 10:32

And the whole earth was of one language (Gen. 11:1). What is written in Scripture before this verse? These are the families of the sons of Noah … and of these were the nations divided in the earth (Gen. 10:32). This is followed by the verse and the whole earth was of one language.

(Gen. 11:1:) NOW THE WHOLE EARTH HAD ONE LANGUAGE. What is written above on the matter (in Gen. 10:32)? THESE ARE THE FAMILIES OF NOAH'S DESCENDANTS.⁹⁴Tanh., Gen. 2:18. Then after that < comes >: NOW THE WHOLE EARTH HAD ONE LANGUAGE. Solomon has said (in Prov. 27:22): IF YOU POUND THE FOOL IN A MORTAR WITH A PESTLE [ALONG WITH THE GRAIN, HIS FOLLY WILL NOT LEAVE HIM].⁹⁵See Gen. R. 38:2. In the case of one who beats the fool, while that one is raising the rod to give him a second blow, he forgets the first time. WITH A PESTLE ALONG WITH THE GRAIN: While he is raising < the rod for > the first time, it is already forgotten. Thus HIS FOLLY WILL NOT LEAVE HIM.