There are many twins around me. They often talk at the same time and it really surprised me. It seems that they can understand each other’s minds. They seem to have some connections between them, which others can never understand.
People call that “twin language”. Sometimes in movies, there would be a type of language which belongs to a secret agency that only the agents understand the language. The same thing applies to twins babies. According to the research, as baby twins develop their ability of talking, they tend to put random words together to represent something that they would understand but others don’t. These words seem to be the tool, similar to codes, for twins to communicate with each other. Although they have their own language, only a small percentage of twins have trouble talking in real English with their parents or other people. Most of them have the ability to switch back and forth between their “twin language” and social language.
According to the research above, there are some correlation between twins and twin language. But correlation does not equal to causation. Being twins does not mean that all of them have twin language. This research is observational so that sometimes it might due to chance. It is also possible that two people stay together for a long time so that tacit understanding is cultivated. We can also see something like twin language between people who are not twins.
Overall, large placebo experiment might need to be done to understand the correlation between twins. It is still possible that twins have a “second language” between them.