I just finished reading this fascinating Smithsonian article by Mike Dash about a Russian family who fled into the Siberian wilderness in 1936 and weren't seen or heard from for 40 years until a team geologists found their home, more than 150 miles from civilization.
"Led by Pismenskaya, the scientists backed hurriedly out of the hut and retreated to a spot a few yards away, where they took out some provisions and began to eat. After about half an hour, the door of the cabin creaked open, and the old man and his two daughters emerged—no longer hysterical and, though still obviously frightened, "frankly curious." Warily, the three strange figures approached and sat down with their visitors, rejecting everything that they were offered—jam, tea, bread—with a muttered, "We are not allowed that!" When Pismenskaya asked, "Have you ever eaten bread?" the old man answered: "I have. But they have not. They have never seen it." At least he was intelligible. The daughters spoke a language distorted by a lifetime of isolation. "When the sisters talked to each other, it sounded like a slow, blurred cooing."