Rouran Khaganate
Alexander Vovin (2007) identifies the extinct Tuoba language (Tabγač) as a Mongolic language. However, Chen (2005) argues that Tuoba was a Turkic language. Vovin (2018) suggests that the Ruanruan language of the Rouran Khaganate was a Mongolic language, close but not identical to Middle Mongolian.