Most of us, at one time or another, imagine what it would be like if there were another person just like us. Twins already know what this is like. They have the same family, the same childhood experiences, and in the case of identical twins, the same DNA, yet they are separate people who eventually build their individual lives. But some twins share more than others.
Shared Language: Grace and Virginia Kennedy
Grace and Virginia Kennedy were born in 1970. The twins suffered a series of seizures soon after birth, and their parents assumed they were left mentally handicapped. The two girls were not sent to school, but kept home with their grandmother (who spoke German and interacted with the children only minimally) while their parents worked. Grace and Virginia's mother spoke German and some English; their father spoke English. However, the girls spoke to each other in a language no one else could understand.
There are many cases of idioglossia, or private language, between twins or close siblings, but in most cases it dies out around age three or four as children socialize with people outside the family. The Kennedy twins, having been isolated from the outside world, continued their strange communication much later. In 1978, French filmmaker Jean-Pierre Gorin made a documentary about the Kennedy twins and their private language. He named it Poto and Cabengo, the names the girls used for each other. Only the first few minutes are available online.
Grace and Virginia were not organically disabled, but suffered from years of neglect. They were studied, analyzed, and sent to school (separately) for the first time, where they thrived. They learned English quickly and social skills slowly. When studied by linguists, their language turned out to be an extremely rushed mishmash of heavily-accented English and German. The family was hoping for a lucrative film deal at the height of their notoriety, but it was not to be. After the girls were sent to school and the novelty of their case wore off, the family retreated once again into isolation.
Shared Personality: Freda and Greta Chaplin
The case of Freda and Greta Chaplin of Yorkshire grabbed public interest in 1981 when the sisters were taken to court for harassing a truck driver they apparently had a crush on. The twins were inseparable: they dressed alike, lived together, moved in sync with each other, and not only finished each other's thoughts, but seemed to speak the same words together.
They also seemed to suffer from a shared mental illness, possibly erotamania, which manifested in their obsession with the truck driver, a neighbor who took them to court after fifteen years of trouble. Later there was speculation that they may be autistic. Freda's and Greta's odd behavior was the centerpiece of a 1994 documentary called The Twins, which is not available online except for this excerpt.
The sisters were inseparable until 2007, when Greta died of cancer at age 64. Frida stays away from the public, and is believed to be in a nursing home.
Shared Mind: Krista and Tatiana Hogan
Krista and Tatiana Hogan (NYT link) are craniopagus conjoined twins, which means they are joined at the head. The four-year-old girls have captivated the scientific community because of a link between their two brains that appears to connect the thalamus of one girl to the other. Neurosurgeon Douglas Cochrane calls this connection a "thalamic bridge," which may send sensory input from one brain to the other.
The twins cannot face the same direction at once, but sometimes one sister will see, feel, or taste something and the other sister will react to the sensation. They are still too young for extensive tests, but will be monitored by scientists studying the brain for years to come.
Shared Body: Abigail and Brittany Hensel
Abigail and Brittany Hensel share more than most of us could dream of. They are dicephalic parapagus twins, joined at the torso in a manner that makes them appear to have one body and two heads. To be precise, there are two of their upper body organs, but their spinal cords join into one pelvis and one set of legs. They were born with three arms, but the rudimentary shared arm was removed. Soon after birth, their parents decided against a separation attempt, as any such operation would leave the girls severely disabled even if they both survived the surgery.
Each twin controls half of their shared body. Abby and Brittany learned to coordinate their movements precisely in order to walk, eat, and perform everyday activities. In 2006, they learned to drive by coordinating their movements and attention, although each had to take a separate test to get a license. The Discovery Health Channel produced a documentary on the twins, called Joined for Life. As of 2011, the 21-year-old Hensel twins were attending Bethel University in Minnesota and are staying out of the spotlight as they focus on their education.
Shared Celebration: Twin Days
Twins naturally occur in one out of every 80 pregnancies. Most twins share only as much as you would expect in siblings who are the same age -which is a lot. The things that twins share are celebrated every year in Twinsburg, Ohio during Twin Days. Twins from all over the world join together to socialize with other pairs who understand what it means to be a twin.