80% of Australian languages are classified as Pama–Nyungan languages. Are you saying they are based off of an Indo-European language?
https://en.wikipedia.org/wiki/Pama%E2%80%93Nyungan_languages
https://en.wikipedia.org/wiki/Pama%E2%80%93Nyungan_languages
Same question: Are you saying they are based off of a Dravidian language?