Hiro fires up Earth while he rides north. He observes that the Raft circulates through the Pacific clockwise, swinging up through southeast Asia, around to Alaska, and then down the West Coast, shedding refugees on rich people's private beaches in California. Fun times.
The Librarian gives Hiro traffic advice and continues to converse about ancient stuff; topics include Kabbalah (medieval Jewish mysticism) and linguistics.
Language universalists (like Chomsky) believe that all languages share a deep structure, even if the languages aren't related and appear to have nothing in common. In theory, brains also start out with the same deep structure, and once people learn languages, the structures of their brains change.
Hiro thinks that Enki understood the relationship between languages and brains, and knew how to hack them—basically, to use language to access and change people's brain structures.
The Librarian summarizes one of Lagos's theories: that the Sumerian language was uniquely suited to spreading information and thus changing people's brains.
So, Hiro says, Babel might've been a good thing for the human race. Everyone speaking different languages = less brain-hacking/mind control.