- Middle Mongol (depending on classification spoken from the 13th century until the early 15th century or late 16th century; given the almost entire lack of written sources for the period in between, an exact cutoff point cannot be established)
- Classical Mongolian, from approximately 1700 to 1900
- Daur - 96,000 speakers
- Central Mongolic
- Southern Mongolic (part of a Gansu–Qinghai Sprachbund)
- Moghol †
Alexander Vovin (2007) identifies the extinct Tabγač or Tuoba language as a Mongolic language. However, Chen (2005) argues that Tuoba (Tabγač) was a Turkic language.
The classification and numbers of speakers above follow Janhunen (2006) except for Southern Mongolic, which follows Nugteren (2011). In another classificational approach, there is a tendency to call Central Mongolian a language consisting of Mongolian proper, Oirat and Buryat, while Ordos (and implicitly also Khamnigan) is seen as a variety of Mongolian proper. Within Mongolian proper, they then draw a distinction between Khalkha on the one hand and Southern Mongolian (containing everything else) on the other hand. A less common subdivision of Central Mongolic is to divide it into a Central dialect (Khalkha, Chakhar, Ordos), an Eastern dialect (Kharchin, Khorchin), a Western dialect (Oirat, Kalmyk), and a Northern dialect (consisting of two Buryat varieties). The broader delimitation of Mongolian may be based on mutual intelligibility, but an analysis based on a tree diagram such as the one above faces other problems because of the close contacts between, for example, Buryat and Khalkha Mongols during history, thus creating or preserving a dialect continuum. Another problem lies in the sheer comparability of terminology l,as Western linguists use language and dialect, while Mongolian linguists use the Grimmian trichotomy language (kele), dialect (nutuγ-un ayalγu) and Mundart (aman ayalγu).