I have suggested earlier that the first 1st sg. pronoun was based on
*mVn- "spirit; man" (and much else) (> PIE *me) which was later
supplanted (partially) by derivatives of (ultimately Austronesian)
*aku (which also seems to have been a noun once).
C. Boisson: The Sumerian Pronominal system in a Nostratic Perspective
in: V. Shevoroshkin (ed.) Nostratic, Dene-Caucaian, Austric and
has for the roots of pronouns in the two dialects of Sumerian
1st sg. g~á
2nd sg. za, zé
1st sg. me
2nd sg. ze
He hypothesizes that Emesal was the more archaic of the two dialects
and that it was a woman's language.
That meshes nicely with my suggestion above that the *egHo(H)(m)
(Dolgopolsky: "not a genuine personal pronoun, but a nominal
substitute for the pronoun *mi") word is a later import, e.g. in a
society that was turning patriarchal as a result of immigration or
import of new ideas.
As for the idea that pronouns were once nouns or noun phrases, cf.
outside of Japanese Polish Pan, Spanish Usted (< Vuestra Merced),
Potuguese você, Dutch U (< Uwe Genade); one might even argue that
Eng. 'your honour' and German 'Ihro Gnade' are (high register)
pronouns of a very limited social context, similarly to the Japanese
Of the form of the earlier 1st sg., from the same article:
Proto-Kartvelian: *me(n) / *mi
Proto-Uralic: *mE, *minV, *munV
PIE *me:, *me
Proto-Turkic: *män-, *bän-
And one shouldn't forget