What is "idioglossia"

n. (context linguistics English) An invented form of dialect, language, or speech used by children, typically twins, and intelligible only to its speakers.

An idioglossia is an idiosyncratic language invented and spoken by only one person or very few people. Most often, idioglossia refers to the "private languages" of young children, especially twins, the latter being more specifically known as cryptophasia, and commonly referred to as twin talk or twin speech.

Children who are exposed to multiple languages from birth are also inclined to create idioglossias, but these languages usually disappear at a relatively early age, giving way to use of one or more of the languages introduced.

Idioglossia is a play by Mark Handley about a girl who grows up without modern culture learning how to speak. It was first performed in 1992 at the George Street Playhouse in New Brunswick, New Jersey. The title comes from the medical term " idioglossia", meaning an idiosyncratic language that few speak, and associated with " cryptophasia".