For the Youlden twins, it has become a common form of communication, but most people eventually lose it.
The twins Both Michael and Matthew Youlden are multilingual in 25 languages. They exclude Umeri, which falls on the 26th, from their count.
There’s a reason you may not be familiar with Umeri. Since Michael and Matthew invented it as kids, they are the only two who can read, write, and speak it.
The brothers maintain that Umeri is not a language that is purposefully kept secret.
“Umeri isn’t ever reduced to a language used to keep things private,” they write in an email. “It undoubtedly holds great sentimental significance for us, as it symbolizes our close relationship.”
Cryptophasia, a shared language or specific communication pattern that is only understandable to the twins, is thought to occur in 30–50% of twins. The word literally means “secret speech” in Greek.
Nancy Segal, director of California State University’s Twin Studies Center, prefers to use “private speech” since she thinks there are now more accurate and nuanced terms for the phenomenon. Segal also refers to speech used inside the pair as “shared verbal understanding” in her book Twin Mythconceptions.
