Like with the elephants, the Smithsonian experts are sure no tribe in America had a language – ever: 

…whenever an alphabet of any kind is veritably discovered, it must have had a foreign origin. By granting belief to anything contravening this state of art, we at first deceive ourselves, and then lend our influence to diffuse error. – Schoolcraft (John Campbell “The Ancient Literature of America,” Proceedings and Transactions of the Royal Society of Canada, Second Series, Vol. II, 1896, pp. 47) 


To admit that even a single tribe in North America had a written language would upset established thought.

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