David Gulpilil did not receive an Oscar nomination for portraying the boy in Walkabout.
David Gulpilil plays an Aboriginal boy the two come across, who is roaming the outback on his Walkabout in which he fends for himself. The boy though takes the two along with him, or at least he allows them to follow him. Gulpili speaks his own native language throughout the film, and the film purposefully eliminates the possibility of understanding him. No subtitles are ever granted to him, and there are very few moments in which the siblings manage to create a direct understanding with him. We are placed in the view of the siblings in this respect as even when the boy does speak it rarely focuses upon in a way in which would even allow one to decipher the words. Of course the film itself does not focus on any of the actors in really the traditional sense. The film seems to care more about the atmosphere of the location and the behavior of those within it more than precisely who they are as people, to the point that it feels like the siblings are supporting as well even though they technically are not in terms of traditional definitions.
Gulpilil therefore has an unusual challenge in that he's not silent, but he's also left without much in terms of verbal communication with the other characters or even the audience. The challenge only becomes more severe due to the nature of the director Nicolas Roeg's approach throughout the film. Gulpilil's performance works well within this structure though as he act natural to be as blunt about it as possible. He never seems to be pantomiming the role of the native, nor does his performance ever seem to be that clichéd restricted view of the native despite the fact there is only a rare occasion that we are given the chance to even know what it is that he is saying. Gulpilil succeeds in being what he should be in that the boy very much becomes sort of the natural expression of the nature around him. This is helped by Gulpilil having a natural charisma of sorts as he manages to have a certain magnetism about him even though this is never a forced intention by his performance. Gulpilil is able to produce this quality without ever seeming to try, which is essential for the role and the film.
Once again the nature of the film and the role does place upon a few severe restrictions on all the performers, since again we mostly witness their behavior with only some emphasis placed on the actual growth of the trio as characters. The major transition is given to Gulpili though in the final interactions between the boy and the siblings, well in this case more of just the sister. This is when the boy decides upon the sister as being more than a travel companion. Gulpilil is quite effective in this scene as he portrays the gradual change in the boy from a mere curiosity in the sister to something far more intense. This leads to the eventual point in which the boy tries to take her as his mate by performing a ritualistic dance after he stumbles upon her half naked. Gulpili is terrific in this scene in that he portrays the moment as more than a primal dance, but also a breakdown of sorts for the boy as the sister outright rejects his advances. Now even this breakdown is still muted in a way by Roeg's choices, despite being well played by Gulpilil. This is a good performance by Gulpili that stands well within the film, even if it does not exactly standout all that much beyond it.