After there had been the great flood, Noah had many descendents. People of the whole world used only one language. They wanted to make a name for themselves. So, they decided to build a city with a very high tower that would reach the sky. In order to do it, they discussed, designed, gathered materials, with one another, bringing workers. At this, they were pleasant and proud of it. As the tower was gradually high, the Lord realized that they have a sense of selfishness to raise themselves up. 

 Then one day, an unusual event happened while they were building a tower. 

 "Lift bricks!" 

 "What did you say? Say again!"

As they used other languages, all of a sudden, that they cannot understand each other, they burst into anger and quarreled. The things happened because God mixed up their language. Eventually, they cannot build a tower that they wanted to do. 

Afterward, those who can understand each other began to live together. From then on, many different languages appeared. 

(Genesis 10:32-11:9)