Poto and Cabengo (names given, respectively, by Grace and Virginia Kennedy to themselves) are American identical twins who used an invented language until the age of about eight.

The girls were apparently of normal intelligence. They developed their own communication as they had little exposure to spoken language in their early years. Poto and Cabengo were the names they called each other.Poto and Cabengo is also the name of a documentary film about the girls made by Jean-Pierre Gorin and released in 1980.