Genesis 11:5 New English Translation

⁵But the Lord came down to see the city and the tower that the people^[a] had started^[b] building.

Genesis 11:5 tn Heb “the sons of man.” The phrase is intended in this polemic to portray the builders as mere mortals, not the lesser deities that the Babylonians claimed built the city.
Genesis 11:5 tn The Hebrew text simply has בָּנוּ (banu), but since v. 8 says they left off building the city, an ingressive idea (“had started building”) should be understood here.

New English Translation (NET)