Laura Spinney in Slate:
In 1882, linguists were electrified by the publication of a lost language—one supposedly spoken by the extinct Taensa people of Louisiana—because it bore hardly any relation to the languages of other Native American peoples of that region. The Taensa grammar was so unusual they were convinced it could teach them something momentous either about the region’s history, or the way that languages evolve, or both.
The reconstruction of the Taensa grammar was the painstaking work of a French teenager named Jean Parisot. He claimed to have stumbled upon a manuscript in his grandfather’s library in the Vosges region of France, and to have realized that it was notes made by unknown explorers who had passed through Taensa territory while the now-extinct people inhabited it.
Parisot’s glory was short-lived. The linguists soon became suspicious about his Taensa grammar: The verbs seemed too regular, the relative clause structure too European. And there were anachronisms in the stories and songs he claimed to have transcribed from the manuscript: They contained references to sugar cane, for example, which had only been introduced to Louisiana, by Jesuits, around the time the Taensa disappeared.
Within a couple of years, Parisot’s grammar had been outed as a hoax and he had retreated to a monastery to take up the religious life.