language 

Some noteworthy (and quite convincing) work has been done by Alexander Vovin that suggests that the Xiongnu spoke a Yeniseian language similar to Ket. This is definitely worth mentioning on the page.

Vovin, Alexander. "Did the Xiongnu speak a Yeniseian language?". Central Asiatic Journal 44/1 (2000), pp. 87-104.

-Andrew