From: P&G
Message: 26014
Date: 2003-09-25
> >There are also cases where the lengthening does not appear.Old Latin (eg Plautus) does write -ess, presumably from -ets. But there is
> I suspect that's the result of a later shortening. In Old
> Latin the ending was written -ess, which I would derive from *-e:ts rather
> than *-its.