Proto-Mongolic is the hypothetical ancestor language of the modern Mongolic languages. It is very close to the Middle Mongol language, the language spoken at the time of Genghis Khan and the Mongol Empire. Most features of modern Mongolic languages can thus be shown to descend from Middle Mongol. An exception would be the Common Mongolic pluritative voice suffix -cAgA- 'do together', which can be reconstructed from the modern languages but is not attested in Middle Mongol.
The languages of the Donghu and Wuhuan might be related to Proto-Mongolic, as well as that of the Xianbei and the Tuoba clan/subgroup (the language of the founders of the Northern Wei) and Khitan. Because the surviving evidence for Xianbei/Tuoba is very sparse, one can hypothesize, but not definitively state, that a genetic relationship could be possible. In the case of Khitan, there is rich evidence, but most of it is written in the two Khitan scripts that have as yet not been fully deciphered. However, from the available evidence it has to be concluded that a genetic relationship to Mongolic is likely.