The origin of the Tocharian A plural ending -äṃ

The aim of the present article is to trace the origin and the evolution of the Tocharian A ending -äṃ, which is the plural marker of a closed class of nouns, whose Tocharian B counterparts are ranged under other inflectional classes. The results of this investigation are twofold: (1) not only is Tocharian A shown to have generally preserved the Proto-Indo-European situation better than Tocharian B, (2) but it is also argued that some members of this closed class are relevant from an Indo-European comparative perspective, since they have refunctionalised the n-form of the PIE *r/n-stems as a plural marker.