Claim: Isaac Asimov (a science fiction writer who wrote or edited over 500 books), wrote Pebble in the Sky about a retired tailor who is transported tens of thousands of years into the future to a place and language he does not recognize, and he is mistaken  as mentally deficient by a couple who take him in and offer him for an experiment to increase his mental abilities.
Evidence: Pebble in the Sky is a science fiction novel by American writer Isaac Asimov, published in 1950. While walking down the street in Chicago, Joseph Schwartz, a retired tailor, is the unwitting victim of a nearby nuclear laboratory accident, by means of which he is instantaneously transported tens of thousands of years into the future (50,000 years, by one character's estimate, a figure later retconned by future Asimov works as a "mistake"). He finds himself in a place he does not recognize, and due to apparent changes in the spoken language that far into the future, he is unable to communicate with anyone. He wanders into a farm, and is taken in by the couple that lives there. They mistake him for a mentally deficient person, and they secretly offer him as a subject for an experimental procedure to increase his mental abilities. He was known for his works of science fiction and popular science. Asimov was a prolific writer who wrote or edited more than 500 books and an estimated 90,000 letters and postcards.