Twins Matthew and Michael Youlden, each fluent in 25 languages, have maintained an extraordinary linguistic connection since childhood through a unique language they invented, called Umeri. While most twins lose any shared language they might develop as children, the Youlden twins’ language has remained a lasting part of their bond and communication style. Interestingly, Umeri doesn’t even make it onto their official language list.
For many twins, creating a shared communication style is not unusual, with an estimated 30-50% developing something linguists call “cryptophasia” – a term rooted in Greek meaning “secret speech.” Cryptophasia often fades as twins begin interacting with a broader social circle and learning formal languages. According to Nancy Segal, director of the Twin Studies Center at California State University, “private speech” or “shared verbal understanding” may be a more accurate description for these twin-specific forms of communication. Segal estimates that around 40% of twin toddlers engage in some form of unique “twin-speak.”
However, for Matthew and Michael, Umeri has become much more than a phase. In an email, the twins shared that, while Umeri wasn’t crafted to be a hidden language, it holds deep sentimental meaning for them. “Umeri isn’t ever reduced to a language used to keep things private,” they explain. “It definitely has a very sentimental value to us, as it reflects the deep bond we share as identical twins.” Originally, they even considered designing a unique alphabet for Umeri before ultimately settling on the Latin script.
The idea of twins developing unique modes of speech often fascinates families, including Roy Johannink from the Netherlands, whose twin children, Merle and Stijn, showed early signs of this “twin-speak.” Johannink captured a memorable moment 13 years ago, posting a video of his babies babbling to each other on YouTube. The video has since gained over 30 million views. Reflecting on the experience, he recalls how the twins seemed to recognize each other as companions, saying, “They thought: ‘Hey, I’m not alone in this moment. There’s another one of me! It’s us against the world.’”
As with most twins, Merle and Stijn eventually lost their private communication as they began speaking Dutch. Segal notes that this pattern of outgrowing “twin-speak” is common once twins gain exposure to people beyond the family. However, the Youldens defied this trend, maintaining and even expanding their use of Umeri as they matured. Now as adults, Umeri remains an enduring reminder of the strong, unique connection they share.
