- Rhotacism applying to cases where other Turkic languages exhibit /z/ or /d/, e.g. Chuvash ura 'foot', tăxxăr, 'nine'.
- /l/ where other Turkic languages exhibit /š/ (sometimes called "lambdacism"), e.g. Chuvash šăl 'tooth'.
- A number of extinct languages are purported to be members of this family. The languages of the Bolgars definitively belong to this branch, and their language is likely the ancestor of Chuvash. Other authors have posited that Avar, Hunnic, and Khazar belong to this branch, although these languages are so poorly attested that it is difficult to be certain that they are Turkic at all.
Róna-Tas, Andras. “Nutshell Chuvash.”