Genesis 10 gives us an account of Noah's 3 sons that were in the ark with him and their lineage. "Those are the tribes of Noah's sons. They are listed by their family lines within their nations. From them the nations spread out over the earth after the flood." (Genesis 10:32)
Genesis 11 is most likely a narrative of what happened during the time described in Genesis 10. We are learning about something that happened as they spread out over the earth. It is useful to note that this happened not too long (in relative terms) after the floodwaters receded. Noah no doubt passed along very intimate details of what happened during that event.
This is probably the motivation for them building a tower so high - to protect themselves should the earth flood again. Although God promised that he would not flood the earth again, this whole episode is about humanity's ego. "Babel" literally means: "a confused mixture of sounds or voices."
Introduce the lesson by speaking in a language that the students are not familiar with. Just a short phrase would suffice. Google Translate is very helpful if you do not know any foreign languages. Or invite guests of different nationalities that speak different languages.
Encourage students to say words in a different language. Teach them to say hello or love in several languages.
For most children, you can read Genesis 11:1-9 directly out of the Bible (especially if you are using an easy-to-understand version like the NIrV). Or, for the very youngest children, read the story from a Children's storybook Bible.
Scripture for Kids to Read Aloud Genesis 11:4, 8-9
First, ask the children if they have any questions about the story. What to do if you don't know the answer?