DISCLAIMER: I'm no expert on the subject, nor am I familiar with these places. This site discusses movies & TV, after all, not geography and anthropology. The information below is gleaned from the film's end credits, Wikipedia and a few extracts from Robyn Davidson's original account of her journey, so it's probably not 100%. Consider this a placeholder until someone more knowledgeable comes along.
First of all, the main language in most of the places mentioned below (and that the real Davidson used in many of the places she visited) is Pitjantjatjara, unless specified otherwise, but the film may have contained many local dialects.
The communities thanked in the Tracks credits:
Anangu Pitjantjatjara Yankunytjatjara. This is a pretty vast area, so if you're looking for something more specific, the real Davidson mentions that she visited Pipalyatjara there.
Kaltukatjara, AKA Docker River. The real Davidson visited this place as well.
Mutitjulu, in the Northern Territory.
Adnyamathanha (which is also their traditional language).
Ngaanyatjarra (which is also their traditional language).
A couple of other places that the real Davidson visited but that might not have appeared in the film:
You can see Robyn Davidson's original route in this picture.