Proto-West-Caucasian: *-a
Meaning: what, who (interrogative stem)
Abkhaz: -a(-)
Abaza: -a(-)
Comments: In Abkh. the meaning of interrogative pronouns is normally expressed by verbal suffixes -da ('who'), -j ('what'). Since d- and j- are class markers (animate/unanimate respectively), the only morpheme to which we can ascribe the interrogative meaning is -a (probably reduced in *-ja > -j). The same morpheme can be seen in -a-ba- 'where' and independent pronouns d-a-rban 'who', j-a-rban 'what' (the -rban suffix is not very clear etymologically - perhaps it contains the root *-ba- 'to see' q.v.?). In Abaz. the situation is analoguous - only in the function of independent pronouns we have d-zač̣ʷǝ-j-a 'who' and j-zač̣ʷǝ-j-a (or ač̣ʷǝja) 'what'. These are derived (by suffixing the same hypothetic interrogative morpheme *-a) from d-zač̣ʷ, j-zač̣ʷ 'each' (ač̣ʷ probably had also existed) where -zač̣ʷ = Abkh. -zač̣ǝ 'single' (from *zA 'one').
