Thread:User talk:CodeCat/Proto-Indo-European/reply (44)

I don't know. *só is kind of odd to begin with because it doesn't have the normal animate nominative ending -s. Some other pronouns also lack it. It's likely that it is a very old word, maybe a holdover from a time before the nominative case existed in its later form. But what the language was like at that stage is anyone's guess.