I found this BBC Travel blog post about the Isle of Man very intesting! In 1974, the last native Manx speaker on the island died. In 2009, Unesco declared Manx extinct, much to the chagrin of the pupils and teachers of Bunscoil Ghaelgagh on the island, who teach only through Manx. They wrote to Unesco, in Manx, to protest and Unesco downgraded the language to endangered. Since 1961, Manx speakers on the island have risen from 165 to 2000+, out of a population of 84,000.