Idioglossia

An idioglossia (from the Greek ιδιογλωσσία idioglōssia, from idio- 'personal' and glōssa 'tongue') 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. An idioglossia (from the Greek ιδιογλωσσία idioglōssia, from idio- 'personal' and glōssa 'tongue') 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.