The plural affix in #Chuvash and its difference from other #Turkic #languages .
One of the most visible differences between Chuvash and other Turkic languages is the plural form, given through affix -sem/-sam, while other Turkic languages use affix -lar/-ler/-tar/-ter and derivatives. This is a consequence of the early branching of the ancestor of the Chuvash language from other Turkic languages - the Chuvash language, as is known, belongs to the Bulgar group and is the only living language.
It is not known exactly when this distinction arose, but already in the Orkhono-Enisean scripts the plural affixes -(X)t/-An/-lAr are used. One could elevate -An to -Am and then to -sAm, but this does not reflect other changes in the Chuvash language.
On one theory, the Chuvash affix -sam/sem is derived from the service word *sajɨn, presumably meaning “everyone, anyone”: *sajɨn -> *-sajna -> *-sajn -> *-san -> *-säm -> -sam/-sem.
This is probably shown in P. S. Pallas's dictionary of the 18th century, in the recorded words in the zone of mixed Chuvash #dialects : vulz’en’é, s’in’s’ämʽ, ač’az’imʽ.
The relic of the original form *-sajɨn we observe in such dialects in the forms of the local and initial plural cases: -senǯe, -senǯen, which goes back not to *-sente, *-sente, but to more ancient forms *-sajɨnta, *-sajɨntan, in which there was a post-jot reduplication.
In the Bulgar dialects ancestral to the Upper Bulgarian dialects, the ancient *-sajɨn in the nominative case in the back row first shrank simply into -san', which did not last long, because it was replaced by the affix -sam, which “got through” from the form of the joint case (similarly to the above-described) (in the epitaph of Olyp-huvaji from 1308 we observe already -sam). The forms of the possessive case are formed from the form -san': -san'in>-san', as well as local and initial: -san'ǯe, -san'ǯen.
