Very few people know this, but in the late 40s there was a major movement to make Esperanto the official language around the world. They even had set a date for the change, something like 1960. During this hype, my grandmother started learning it, she can speak it.

In case you don't know, Esperanto is a fabricated language, created in the XIX century to serve as a universal language. It is simple to learn, and a lot of enthusiasts speak it nowadays. There are several books written on it, and even a few films spoken in Esperanto. It's mostly used as a device to meet people, create groups, and stuff like that.