On Sat, 1 Jun 2013 09:51:44 +1200, yuri <[log in to unmask]> wrote:

>Actually, when I first saw the subject line I thought this was going
>to be a thread about tenses used by a time travelling conculture.
>Past, present and future wouldn't suffice. You and I could be
>discussing an event that happened in MY past but in YOUR future.

It's hardly a matter of "suffice"; it's just that certain implicatures of the use of certain tenses might no longer hold.  Supposing the relevant notions make sense in your time travel physics[0], the tense system might mark only time differences in the "absolute" timeline, or only time differences in the speaker's experiential timeline; nothing's wrong with either, though they might be less useful.  (Or both could exist as orthogonal systems; or other variants.)

Indeed, it's already the case that you might be telling me about an event that happened in MY past but in YOUR future -- that's the great thing about writing, or other forms of recording language!  Yet we get by.  (AFMCL, UNLWS has long been planned to have a second series of reader-based temporal deictics, though we haven't made up the forms.)

That said, JBR probably has the right of it: the cleanest system is just to forego tense as an inflectional category!  I suspect that if time were less totally-ordered-for-everyone, and practically speaking were really just a fourth dimension events can be positioned in without much that's functionally special about it, then crosslinguistically tense inflection on the verb would recede to about the (much lower) frequency that position-in-space inflection on the verb has *here*.

[0] In general, the more narratively compelling a model of time travel is, the less likely it is to have a physics of any consistency (though Primer is a pleasant exception) -- see higher up on that page of JBR's.