I just got some examples from Kurdish that show a really odd trend with
their split ergativity.  I'll make up a language that does the same thing so
that it's regular and easily identifiable.

bo=I (1st person)
-na=past tense
-b=agreement with 1st person for verbs
-k=agreement with 2nd person for verbs
-n=object marker

    Notice, I didn't write anything like "ergative" or "absolutative" there.
Watch how these exmaples go:

Present Tense:
1.) bo malab.  ("I run", present tense.)
2.) bo kun gabab.  ("I see you" present tense.)

    As I said, Kurdish is a split ergative language, so it maintains an
accusative structure in the present.  Now, onto the past and the ergativity.

Past Tense:
3.) bo malanab.  ("I ran")
4.) kun bo gabanak.  ("You saw me.")

    Look at number four!  Essentially what you've done from number two to
number one is put the verb in the past tense, switch the order of the
pronouns and made the verb agree with object instead of the subject.  That's
exactly what Kurdish does!  It's as if in the switch from present to past and
accusative to ergative they switched the semantics of the affixes!  It's so

    On a side note, has anyone heard anything about Swedish, Japanese and
Serbo-Croat being pitch-accent languages?