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.
Grace and Virginia were born in 1970 in Columbus, Georgia. Their birth was normal, and they were able to lift their heads and make eye contact with their parents within hours after birth, but both soon suffered apparent seizures. Their father maintained that a surgeon told him the girls might experience developmental disabilities. Misunderstanding speculation for diagnosis, the girls' parents ceased to pay more attention to them than necessary.
Both parents were employed (although later characterized by The San Diego Tribune as living on "food stamps and welfare") and spent many hours away from home. The girls were left in the care of a grandmother who met their physical needs but did not play or interact with them. The grandmother spoke only German, while the parents spoke English. They had no contact with other children, seldom played outdoors, and were not sent to school.
Their father later stated in interviews that he realized the girls had invented a language of their own; but, since their use of English remained extremely rudimentary, he had decided that they were, as the doctor suggested, developmentally challenged and that it would do no good to send them to school. When he lost his job, he told a caseworker at the unemployment office about his family; and the caseworker advised him to put the girls in speech therapy. At the Children's Hospital of San Diego, in California, speech therapists Ann Koeneke and Alexa Kratze quickly discovered that Virginia and Grace, far from being mentally impaired, had at least normal intelligence and had invented a complex idioglossia.
The language of the twins was spoken extremely quickly and had a staccato rhythm. These characteristics transferred themselves to the girls' English, which they began to speak following speech therapy. Linguistic analysis of their language revealed that it was a mixture of English and German (their mother and grandmother were German-born), with some neologisms and several idiosyncratic grammatical features.
The story of the "twins who made their own language" made the national newspapers in 1978 and was included in an edition of the People's Almanac. Many speech and hearing experts, as well as psychiatrists, offered speculation as to why the girls had not picked up English, as most idioglossic twins do whether or not they retain their personal language. Kratze pointed out that the girls had had very little contact with anyone outside their family, and that contact within the family had been minimal at best. These factors contributed to the girls' developmental disability, even if they had been born with normal intelligence.
Once it was established that the girls could be educated, their father apparently forbade them to speak their personal language. He was quoted in Time magazine as saying "They don't want to be associated as dummies. You live in a society, you got to speak the language." Asked if they remembered their language, the girls confirmed that they did, but their father quickly stepped in to chide them for "lying". They were mainstreamed and placed in separate classes in elementary school. However, they were still affected by their family's emotional neglect. A follow-up in 2007 revealed that Virginia works on an assembly line in a supervised job training center, while Grace mops floors at a fast-food restaurant.
"Pinit, putahtraletungay." (Finish, potato salad hungry)
"Nis, Poto?" (This, Poto?)
"Liba Cabingoat, it." (Dear Cabengo, eat)
"La moa, Poto?" (Here more, Poto?)