The system of nominal declensions was largely inherited from PIE.
Syllable-final *n (from PIE *m, *n) assimilated to the following phoneme, include across word boundaries in the case of syntactically-connected words.
The specific form of this pronoun can be derived from PIE *yū(H)s (2nd plural nominative).
These stem categories descend from PIE, and can therefore be compared to similar conjugations in other IE languages.
After those two blokes from PIE came round soliciting and went away with thick ears.
It was likely removed less than a millennium from the Avestan language, and less than two millennia from PIE.
This can also be seen in the third conjugation of Latin, which includes most verbs directly inherited from PIE.
The present participle (from PIE *-nt-) still retained consonant stem endings.
-Tur is the mediopassive present 3rd person singular from PIE *-tor) with the same usage.
Derived from PIE perfect.