Forty languages are still spoken in Oklahoma, Texas and New Mexico, many of them originally used by Indian tribes and others introduced by Eastern tribes that were forced to resettle on reservations, mainly in Oklahoma. Several of the languages are moribund.

Another measure of the threat to many relatively unknown languages, Dr. Harrison said, is that 83 languages with “global” influence are spoken and written by 80 percent of the world population. Most of the others face extinction at a rate, the researchers said, that exceeds that of birds, mammals, fish and plants.

—"Languages Die, But Not Their Last Words," John Noble Wilford, New York Times, September 19, 2007.