What does Genesis 11:7 mean?
At this point in history, the peoples of the earth remained undivided, with one language and culture. They had also decided to remain unified and become great and powerful by their own strength and ability. They did not apparently worship God or call to Him for help.So, God "came down," and saw the great city and tower they had made. The verse uses the phrasing "let us" with respect to God. Similar language is used in Genesis 1:26 and 3:22. God may be speaking to Himself within the Trinity of Father, Son, and Holy Spirit. Alternatively, He may be commanding the angels to come and participate.
In either case, God acknowledges that by working together, nothing would be impossible for humanity. More specifically, God points out that mankind is capable of enormous evil, when their sinful natures become aligned. God is not attempting to stifle mankind's potential to accomplish "anything" good, but He is very concerned about their potential to accomplish "anything" evil.
God decides to stop their progress by dividing the people according to language, for starters. People who speak different languages have an immediate barrier to communication, making it harder to cooperate. Further, this would naturally begin to separate people into groups, based on those languages, and in fulfillment of God's intent for man after the flood (Genesis 9:1).