Cryptophasia is a phenomenon that mostly occurs in twins. The word derives from Greek, with ‘crypto’ meaning secret, and ‘phasia’ meaning speech. As the name suggests, it is a language developed by twins that only the two children can understand. British psychologist, Dorothy Vera Bishop, writes that this phenomenon occurs in 50% of twins because they are in close proximity and may be very reliant on each other. Quite often, twins will phase out of their cryptophasia when they start gaining exposure to people beyond the home. However, for Poto and Cabengo, the Youlden twins, and the Gibbons twins (The Silent Twins), this did not happen.  

Poto and Cabengo: 

Poto and Cabengo (Grace and Virginia Kennedy) are American identical twins who created their own language and continued it up until they were eight. Usually with twins that create a cryptophasia, they lose it by the time they enter school or nursery. However, unlike most twins, Grace and Virginia spent a lot of their young childhood without external stimulus to their language development. The girls were left in the care of a grandmother who met their physical needs but did not play or interact with them. They had no contact with other children, seldom played outdoors, and were not sent to school. Their father later stated in interviews that he realised 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. 

The twins’ language was characterised by an extremely fast tempo and a staccato rhythm, traits the girls transferred to their spoken English following speech therapy. Linguistic analysis revealed that their language was a mixture of English and German, German through their limited interaction of their mother and grandmother and English through their father, with some neologisms and several idiosyncratic grammatical features. 

Sample speech: 

‘Pinit, putahtraletungay’ (Finish, potato salad hungry) 

‘Liba Cabingoat, it’ (Dear Cabengo, eat) 

Once it was established that the girls could be educated, their father apparently forbade them to speak their personal language, and they went to school, which phased out their cryptophasia (however, it is reported that the twins still know their cryptophasia).  

The Youlden Twins: 

Twins Matthew and Michael Youlden speak 25 official languages each and one cryptophasia – Umeri. Like 50% of twins, the Youlden twins developed a cryptophasia at a young age but did not grow out of it as they became exposed to the world outside of the home. Instead, the multicultural aspect of Manchester, UK fostered their love of language which inspired them to learn languages like Spanish, Italian and other Scandinavian languages. Pooling together various grammatical elements of all the languages they studied, they created Umeri. The twins began to codify and standardise the language in which Umeri is now written using the Latin alphabet. To this day, the Umeri language is being continuously expanded to adapt to modern life.  

Since the twins’ language goes beyond the standard convention of cryptophasia, child development and education specialist, Karen Thorpe, describes the twins’ cryptophasia as being about ‘a very close relationship’ rather than the secret or private language cryptophasia is associated with.   

The Silent Twins (Gibbons Twins): 

While the full Gibbons story is incredible in its own way, linguistically, their cryptophasia branches beyond linguistics and into psycholinguistics. Jennifer and June Gibbons, twins of Caribbean parents who migrated to Wales in the Windrush era due to their father’s job in the Air Forces, were inseparable. Their language (cryptophasia) was a sped-up Bajan Creole, which made it difficult for people to understand them. In 2023, June said, “We had a speech impediment. Our parents couldn’t understand a word that we were saying, nobody understood – so we stopped talking.”   

The Gibbons children were the only black children in the community and were often ostracised at school. This proved to be traumatic for the twins, eventually causing their school administrators to dismiss them early each day so that they might avoid bullying. Their language became even more idiosyncratic at this time. Soon it was unintelligible to others as they continued to speak to no one but each other. While June Gibbons disputes the idea that their idioglossia is a form of cryptophasia, linguistically, their language usage is categorised as cryptophasia.  

Their cryptophasia ended when Jennifer died. According to the twins’ father, Wallace, the girls had a longstanding agreement that if one died, the other must begin to speak and live a normal life. As of 2008, June is living quietly and independently, near her parents in West Wales.  

Cryptophasia is a unique and mysterious phenomenon that highlights the fascinating connection between language and relationships and must be researched further in the linguistic field. Whether it is the secret language of twins like Poto and Cabengo, the evolving multilingual system of the Youlden twins, or the deep, psychological bond behind the Gibbons twins’ cryptophasia, these stories show just how powerful communication can be when shaped by isolation, love, and shared experience. While most cryptophasias fade as children grow and interact with the world, these cases remind us how language is not just about words—it is a reflection of connection, creativity, and sometimes survival.