A single language appears to have been spoken in a triangle that stretched from somewhere north of Lacepede Bay on the coast of South Australia across to Bordertown on the Victorian border and south to the coast where the mouth of the Glenelg in far western Victoria formed the south-eastern corner. A consideration of various references indicates clearly that the territory of the Buwandik, alternatively Bunganditj, extended to the mouth of the Glenelg and further north it extended to Coleraine and perhaps Balmoral.
Practically all our data comes from old sources. There are twelve sources of vocabulary for the language and two direct sources of grammatical information on the dialect spoken by the Booandik or Bunganditj. One source for the grammar is a sketch of three pages by D.S. Stewart; the other is a slightly longer sketch by R.H. Mathews, which exists in two forms, manuscript and published. Some further grammatical information can be obtained from the 'Mount Gambier' sentences in William Thomas' Dialogues in six dialects (details below), and a few further scraps can be gleaned from the word lists, specially from the one by Stewart which accompanies his grammatical sketch.