OK, so having decided to run with akam chinjir's idea, I'm going to try to build this up step by step from first principles. Where possible, I have tried to avoid specific terminology (such as ergative, absolutive etc) where this might convey implications that are not necessarily the case.
Basic principles:
Regardless of its "semantic transitivity",
each verb is morphosyntactically monovalent. That is, it obligatorily selects one (and only one) core argument.
Morphosyntactic marking is concerned with
intention and affect: who intended this action, and who/what was affected.
The loci of marking in the verb phrase are the verb itself, which marks affect, and the verb's single argument, which marks intention.
A bit of terminology and morphology:
Verbs can be divided into two groups: stative, which express a state; or dynamic, which express a change in state or an action. This is a semantic property and does not have overt inflectional marking[1].
The verb can take one of two "versions"[2]: the effective *
a~ä; or the affective *
u~o. The latter is more "marked" than the former.
The single core argument of a verb is referred to as the
specifier[3].
The specifier can take one of two cases: the accidentive *
a~ä; or the intentive *
u~o. Again, the latter is more "marked" than the former.
Instantiation:
Stative verbs, logically, do not affect anything nor can they be intended by anyone. As such, both verb and specifier take the least marked inflectional categories:
piykʰa wetɬä
- piykʰ
- girl
- -a
- -ACD
- wetɬ
- sleep
- -a
- -EFF
"The girl sleeps."
Moving on to dynamic verbs, if an action is intended then the specifier is marked with the intentive case:
päytʰo ŋara
- päytʰ
- boy
- -u
- -INT
- ŋar
- break
- a
- -EFF
"The boy breaks something (on purpose)."
And if it is unintentional, then the accidentive case is used:
päytʰä ŋara
- päytʰ
- boy
- -a
- -ACD
- ŋar
- break
- a
- -EFF
"The boy breaks something (accidentally)."
So far, the example verbs have used the effective version. The effective version is essentially agnostic as to who/what is affected by the verb. By contrast, the affective version indicates that the specifier is affected by the verb in some way. Compare:
tanu pʰetnä
- tan
- man
- -u
- -INT
- pʰetn
- wash
- -a
- -EFF
"The man washes something."
tanu pʰetno
- tan
- man
- -u
- -INT
- pʰetn
- wash
- -u
- -AFF
"The man washes himself/the man washes something for his own benefit"
The affective version can be used in conjunction with a specifier in the accidentive case:
tana xʷoso
- tan
- man
- -a
- -ACD
- xʷos
- rain
- -u
- -AFF
"The man got rained upon."
To expand somewhat, the affective + intentive often has a reflexive or benefactive meaning, while the affective + accidentive often has a "passive" or even "malefactive" meaning. Compare:
tanu saɣtu
- tan
- man
- -u
- -INT
- saɣt
- kill
- -u
- -AFF
"The man killed himself / the man killed something or someone for his own benefit."
tana saɣtu
- tan
- man
- -a
- -ACD
- saɣt
- kill
- -u
- -AFF
"The man got himself killed."
Adjuncts, or adding other participants:
Non-core arguments can be introduced to the verb phrase by means of a noun in the oblique case (marked with *
i~e). Nouns in this case are underspecified for their precise thematic role. For example, the sentence:
piykʰu ʔisɣi saɣta
- piykʰ
- girl
- -u
- -INT
- ʔisɣ
- fish
- -i
- -OBL
- saɣt
- kill
- -a
- -EFF
Could mean "the girl killed the fish" or "the girl killed something in the manner of a fish" or "the girl killed something using a fish".
Similarly, one should resist the temptation to analyse a sentence like
päytʰä motkʰe saɣtu
- päytʰ
- boy
- -a
- -ACD
- motk
- cave.bear
- -i
- -OBL
- saɣt
- kill
- -u
- -AFF
as being a simple "passive" construction like "the boy was killed by a bear". Another possible reading is "the boy accidentally killed something in the manner of a bear, which had an adverse impact upon him" (for example, maybe he accidentally crushed his baby sister to death and this has led to him being shunned by the rest of his tribe).
Furthermore, the sentence
päytʰo motkʰe saɣtu
- päytʰ
- boy
- -u
- -INT
- motk
- cave.bear
- -i
- -OBL
- saɣt
- kill
- -u
- -AFF
could mean "the boy killed a bear for himself" or "the boy committed suicide by bear", or even "the boy won himself renown by killing something in the manner of a bear". Context alone serves to supply the correct meaning: the first implicature would be the most likely if one saw a boy dragging a bear back to camp, the second if responding to a question about why we no longer see the boy around any more and the third perhaps if one asks why a small boy is being celebrated and treated with deference.
The above examples have used semantically transitive verbs, but the same considerations apply with semantically intransitive verbs:
tseɣro motkʰe naɣa
- tseɣr
- shaman
- -u
- -INT
- motk
- cave.bear
- -i
- -OBL
- naɣ
- approach.the.speaker
- -a
- -EFF
The above sentence could, for example, mean "the shaman summoned the bear for me" or "the shaman came towards me like a bear" (or, indeed, it could have both meanings at the same time).
While these fine distinctions can of course be made more explicit by means of postpositions, my point in giving the variant readings above is that no particular implicature is favoured above another. The oblique case does not necessarily introduce an argument which satisfies the semantic transitivity of a given verb.
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[1] That is not to say that it cannot be marked through derivational processes.
[2] I have preferred this term to "voice", as the latter is often used as a term for a phenomenon which increases or decreases a verb's valence, which is not possible in this language.
[3] This is a term stolen from X-Bar theory and entirely misapplied in this case. However, it avoids the connotations of "subject".
