He was born Graf Heinrich Karl Wilhelm Ottot Friedrich von Ubersetzenseehafenstadt...."
It's a nonsense name. And as Wandel JW said, it's a play on the German habits to form big words by stringing small words together. (For a satirical account that hits the nail on the head, see Mark Twain's article The Ugly German Language
which should be easy to find on the web.)
"Ubersetzenseehafenstadt" is a city name Neal Stephenson strung together this way. As I said, the name is nonsense, but the pieces it was strung together from are valid German words. Let's parse it: "Uebersetzen" can mean either "to translate" or "to traverse a body of water", usually a river or a lake. "See" means lake, "Hafen" means harbor, and "Stadt" means city.
It's impossible in English to put the pieces back together in a way that makes sense. And I suspect that's the point Stephenson is making about the German language.