"Cryptophasia" is the term for the secret languages that apparently 40 percent of identical twins develop. Nautilus investigates:
The most famous example of cryptophasia is identical twins Ginny and Grace Kennedy from California. A documentary and many articles, including two 1970s features in Time magazine, captured the private lingo of the twins who called each other Poto and Cabengo:
"Pinit, putahtraletungay" (Finish, potato salad hungry)
"Nis, Poto?" (This, Poto?)
"Liba Cabingoat, it" (Dear Cabengo, eat)
"la moa, Poto?" (Here more, Poto?)
"What you find is that the words are approximations of adult language," says Peter Bakker, professor of linguistics at Aarhus University in Denmark, author of what remains the deepest and widest study of cryptophasia, "Autonomous Languages," published in Italian twins research journal Acta geneticae medicae et gemellologiae in 1987.