Obviative/Proximate and the Omaha verb system

[Koontz John E]

I've been pondering the conditioning of bi vs. i as the plural/proximate
marker and I'm beginning to wonder if bi doesn't occur in mainly irrealis
contexts or something like that, which is not far in some ways from what
Rory claims.  It occurs with ama, with negatives, with at least some
clause markers variably - and I have to check that), and with clauses
under 'to think'.  It does also occur in songs and names, which seems a
separate case or cases.  I do think that bi and i are otherwise synonymous
and "interchangeable."  (Subject to bi having an additional feature.)