[…] the purpose of delaying autoops is basically reducing the number of mode changes, and grouping several oppings into one.

The most probable foreform must have been the Old Ir. Acc.Sg.f., that is *ayam (cf. Av. imí|m, aeümi).

Stay, dear, you will disarrange your curls—let me untie your hat.

The Prime Minister insisted on his Chancellor's resignation.