I met N. Scott Momaday, a Kiowa Indian who is a Pulitzer Prize winning novelist and a scholar at Brainstorm last year. He left a great impression on me with his great stories. This year during the session on the Commons, we were all talking about the economics of who manages the commons. He said that language was a commons and that stories that have been passed down through generations lived in these commons. I had never thought of language itself as a commons, but it's a great example.
He also said that from a Native American perspective, land was a commons and language was a commons. Land was where we come from and return to. Language was where we lived. (He said it much more poetically than I can, but I can't remember exactly what he said.)