bushmen have a very interesting language-- its the only surviving one with clicks (!) and whistle like noises.
Not knowing what the proto-language was, I can't say for certain whether Khoisan languages preserve clicks or innovated them after the others left. We use clicks in English, just not as phonemes in words: e.g., kissing sound, gee-up, and the interjection transcribed as tsk-tsk.
The interesting thing about the Australian Aborigines is how they seem to have left little behind genetically while traveling to Oz. As I remember the PBS special, the South Indians are not that closely linked with them. Later arrivals?
There's a danger in equating "race", language, culture, and material artifacts that makes me nervous given the nature of the century in which I grew up. How much genewise did the Romans contribute to the Gaulish population? We know their impact linguistically. Then look at the Franks. They left loanwords, but French is still basically Neo-Latin. Or the Vandals in Northern Spain or the Lombards in Italy.
