The Northern Athabaskan languages are the largest group in the Athabaskan family, although this group varies internally about as much as do languages in the entire family. The urheimat of the Athabaskan family is most likely in the Tanana Valley of east-central Alaska. There are many homologies between Proto-Athabaskan vocabulary and patterns reflected in archaeological sites such as Upward Sun, Swan Point and Broken Mammoth (Kari 2010). The Northern Athabaskan group also contains the most linguistically conservative languages, particularly Koyukon, Ahtna, Dena'ina, and Dakelh/Carrier (Leer 2008).