Why did many Aboriginal languages disappear before linguists could record them?

Many Australian Aboriginal languages became extinct before they could be systematically recorded by linguists primarily because they disappeared following European contact. Because these languages were often lost before formal documentation could occur, much of what is known about them—if anything at all—is derived from fragmentary and poorly transcribed word lists created by missionaries.1

The challenge of documenting these languages is further complicated by the difficulty of distinguishing between distinct languages and dialects. While a major collective effort to record surviving languages began in the early 1970s, many varieties had already been lost, leaving researchers with limited data to reconstruct the linguistic history of the continent.1