Eyak
Krauss' largest contribution to language documentation is his work on Eyak, conducted through much of the 1960s. Eyak was then already the most endangered of the Alaskan languages, and Krauss' work is all the more notable considering that it represents what today might be considered salvage linguistics. While some Eyak data had been previously available, they were overlooked by previous scholars, including Edward Sapir. However, Eyak proved to be a crucial missing link for historical linguistics, being equally closely related to neighboring Ahtna and to distant Navajo. With good Eyak data it became possible to establish the existence of the Athabaskan–Eyak–Tlingit language family, though phonological evidence for links to Haida remained elusive. Further, the system of vowel modifications present in Eyak inspired Krauss' theory of Athabaskan tonogenesis, whereby tone develops from vowel constriction.
Read more about this topic: Michael E. Krauss