Q My twin boys will be three in March. For the last 12 months or so, they have been calling each other by different names to the ones we gave them! Both still answer to their actual names, but refer to each other with their created names. It's quite entertaining as you can imagine, and they don't seem to be doing it for attention. Have you any idea why they are doing this?
David replies: Today seems to be my day for short answers, and my short answer is no, I have no idea why they are doing it. I have heard about twins creating their own unique language, called cryptophasia. It is thought that cryptophasia occurs when twins make errors in pronunciation in the early stages of their language development (as all small children will have idiosyncratic ways of pronouncing words).
In other circumstances, the pronunciation errors get corrected by adults or older children, but for twins, with the closeness of their bond, those personalised ways of pronouncing things become understood and used by each other, with no great need to change or adapt to the language being spoken by others around them. It usually fades away as they grow older. But this isn't really the issue for your boys.
Perhaps your twins have simply adopted "pet" names for each other, just as some children are given a name at birth, but then get referred to by everyone by a preferred or pet name. At least you are entertained, rather than frustrated, by their renaming of each other!