Detail #238: Onwards with #237, into 'odd subjects and objects'

Let us consider a noun class system where a variety of nouns have 'typical' non-subjectlike associated roles, e.g. members of one class are likely to be used as instruments (mainly tools), members of another are likely to be locations (mainly places, buildings, and certain actions that take place in specific places), members of a third class are likely to be direct objects (inanimate non-tools), and members of one class are likely to be time-spans or directions (day, downriver (as a noun), upriver (likewise), south, north, downwind (as a noun), etc).

Now, each of these noun classes lacks a classical nominative - they do have an unmarked form though, it's just that it's half-nominative half-whatever the class is associated with (instrumental, accusative, lative, locative, ...) - and the same goes for the object case. They can be parsed as subjects (or for the object case, as objects), indeed, but can also be parsed as instrumentals (for the first example), locations (for the second example), direct objects (...), or time-spans or directions (...)

All other nouns can be marked using cases to have these roles (except that time-spans may be somewhat restricted, although 'until X (arrives|finishes)' can be an interpretation, as well as 'for X's reign|presence|as long as X keeps doing whatever he's doing' could be meaningful interpretations there as well. 

So, the verb can take congruence with the noun in the pseudo-nominative, and if the noun is the topic, subject agreement is necessarily congruent with that noun's class. These nouns therefore permit for unmarked pseudo-circumstantial voice whenever they're present or in topic position. When they're direct objects, they permit for unmarked pseudo-applicative voices. Any 'real' agent or patient of the verb would be forced to be oblique.

So, a verb voice system with no verbal voice marking, voice marking instead being entirely reliant on the noun classes of the noun that the verb agrees with, or the noun in the direct object slot - however, with the extra challenge that these nouns could also be regular subjects or direct objects. Disambiguating such regular subjects and objects can be done by making them oblique, though, although this approach must be used sparingly or the language would turn the oblique markings into the 'real nominative' and 'real accusative'.

One fun thing is that this would permit really strange combinations of applicative and circumstantial, such as hammer strikes day: there is hitting with the hammer for the duration of the day, day strikes hammer: for the duration of the day there is hitting with the hammer.

Of course, one could also imagine classes that have different meanings when in subject position and when in object position - or maybe some nouns reside on the edge of one class, with one foot in another.