An idioglossia (from the Ancient Greek ἴδιος ídios, 'own, personal, distinct' and γλῶσσα glôssa, 'tongue') is an idiosyncratic language invented and spoken by only one person. 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.