Lately I’ve been thinking about the origins of the Yivrian passive (and how it’s related to the Praseo passive, and if Praseo even has a passive). Eventually I wrote up the following, which I am very pleased with:
In Common Yivrian (CY), the thematic vowel of the verb has three grades1, which are reflexed in Yivrian (Y) but with different semantics:
Base -yā Focus -yō Intensive -yū
The base form is most commonly used and has unmarked semantics. The focus form is used when the verb itself carries the discourse focus. This form becomes the Yivrian passive, and is the topic of the following discussion. (The intensive form in CY is outside of the scope of this discussion, but it eventually becomes the Yivrian reflexive.)
In CY the default word order was SVO, though the case-marking allowed for mild nonconfigurationality, with the order of subjects and objects relative to each other and to the verb being unconstrained. This word order was exploited for discursive purposes, with the utterance-initial position serving to indicate focus. Nouns had no additional marking for focus, but as mentioned above when you wished to focus the verb, the thematic vowel of the verb ending changed:
Unmarked word order:
[CY] Daθu leθθyā nawimu. Bird eat worm-ACC "The bird eats the worm."
Verb-focused word order:
[CY] Leθθyō nawimu daθu. eat-FOCUS worm-ACC bird "It *eats* the worm, that's what the bird does."
This could be used with stative verbs as well:
[CY] Hāðiyōhi yīse. Be-beautiful-FOCUS woman. "The woman is *beautiful*."
This latter case has survived essentially unchanged into Yivrian, where an intransitive verb can be marked for focus by being marked with -o and moved to the beginning of the sentence.
[Y] Harayoa nayiise. Be-beautiful-PASS that-woman. "That woman is *beautiful*."
However, the semantics and syntax of this sentence are somewhat changed from what they were in CY, due to the concomitant changes to the transitive case. The transitive verb-focused statements were reinterpreted as passives due to the following three changes:
The accusative case marker was lost. Since previously verb-focused sentences could have VSO or VOS word order, this caused an ambiguity.
To disambiguate agents from patients in verb-focused transitive sentences, the agent was marked with the instrumental case.
Once the agent was marked by the instrumental case, the now-unmarked object was reinterpreted as the syntactic subject, and the verb-focus marker was reinterpreted as a passive marker.
Yivrian retains vestiges of this system in its word order. The unmarked word order for active transitive sentences is SVO, but passives are VS(A), with the agent optionally indicated by an oblique argument in the ablative case. (The Yivrian ablative conflates the old instrumental and locative cases.) For examples of each type:
[Y] Doth lethya na. Bird eat worm. "The bird eats the worm." Lethyo na dathun. Eat-PASS worm bird-ABL. "The worm is eaten by the bird."
The VS(A) word order for passives was the normal word order throughout the classical period, and passives with the SV(A) word order that more closely mimicked the active word order were rare. They become more common in post-Classical Yivrian, as the passive significance of the verb marking becomes more salient and the verb-focusing origins of the construction are lost.
For intransitive verbs the passive -o retained its role as a marker of verbal focus. However, once -o was understood primarily as a passive transformation, the argument-reducing aspect of the passive voice was applied to intransitives as well. Thus, if you wish to omit the subject of an intransitive verb, you must apply the passive morphology to it as well. This is a special case of the verb-focused intransitives discussed above.
[Y] Volassumyoa. INTENSIVE-be-stupid-PASS-PROG "Someone sure is being stupid."
Finally, ordinarily subject-less verbs such as weather verbs were influenced by this pattern. In CY (and in both Praseo and Tzingrizhil), such verbs take the ordinary verbal ending -a, but in early classical Yivrian we find them occurring oftentimes with -o, and by the late classical period the passive marking of such verbs has become obligatory.
[Y] Lavyon kayana. rain-PASS-FUT tomorrow. "It will rain tomorrow."
These grades are very similar to the ā/ō/ū grades found in the stative nouns (Yivrian nouns of emotion), and probably are etymologically related.↩