These were the families of the sons of Noah, according to their generations, in their nations; and from these the nations were divided on the earth after the flood. (GENESIS 10:32)
The Bible in Genesis 10 gives a list of families that came out of Babel with new languages. Since we don’t know how many people were in each family, we can’t know the exact number of people who came out of Babel. If we add up the families, there were at least 78. There could have been a few more, since the line that goes from Noah to Peleg (ultimately the line of Jesus) doesn’t give us all the information. For example, this line contains Noah, Shem, Arphaxad, Selah, Eber, and Peleg. (Some of these sound like strange names, huh?)
But GENESIS 11:13 says that Arphaxad had other children. GENESIS 11:14 says that Selah had other children. And GENESIS 11:17 says that Eber had other children as well. So these families that were not listed specifically in Genesis 10, but mentioned in Genesis 11, may have had a new language and would add to those 78 families. If each of these 78 families had a dad, a mom, and three kids, that would be just under 400 people! One person named Joktan had 13 kids (GENESIS 10:26–29). So some families may have had much more than just three children.