The Indigenous languages of Australia number in the hundreds, the precise number being quite uncertain although there is a range of estimates from a minimum of around 250 (using the technical definition of 'language' as non-mutually intelligible varieties) up to possibly 363. The Indigenous languages of Australia comprise numerous language families and isolates, perhaps as many as 13, spoken by the Indigenous peoples of mainland Australia and a few nearby islands. The relationships between the language families are not clear at present although there are proposals to link some into larger groupings. Despite this uncertainty, the Indigenous Australian languages are collectively covered by the technical term "Australian languages", or the "Australian family".