Language isolates are languages with no demonstrable relationship to other languages, in effect, language families with a single member. All classifications of Australian languages, from Schmidt onwards, include language isolates within the Australian continent. That is, setting aside the putative status of descent from a common Proto-Australian, all authors recognize a series of single languages with no close relatives. Several languages of off-shore islands, particularly Tiwi and Anindilyakwa, are very divergent from their nearest geographic neighbors on the mainland. It is often assumed that long periods of diversification in isolation have led to languages that share very few features with their neighbors. Anindilyakwa is spoken on Groote Eylandt. It has approximately 1300 speakers, according to the Australian national census from 2006. In some cases, the classification of languages shifts depending on the catalogue but in no case is evidence presented in favor or against a particular classification.