We already learned that the argument nearest to the verbs is the PATIENT / CORE ARGUMENT. We also learned that to promote that argument to an AGENT we double the verb.
‘Aranna
‘ara nöna
boy eat
(Something) eats a boy. Â or
A boy is eaten.
‘Ara nnanna
‘ara nöna nöna
boy eat eat
A boy eats.
‘Nna’ara
nöna ‘ara
eat boy
(Something) eats the boy. Â or
The boy is eaten.
Nnanna ‘ara
nöna nöna ‘ara
eat eat boy
The boy eats.
Straddled Verbs
We also learned that when there are arguments on both sides of the verb, the definite (post-verbal) argument is assumed to be the AGENT.
 Â
Me’unna ‘ara
me’u nöna ‘ara
shark eat boy
The boy eats a shark.
 Â
‘Aranna me’u
‘ara nöna me’u
boy eat shark
The shark eats a boy.
I quoted The Languages of Native North America by Marianne Minthum.
It is now well known that speakers of most languages rarely introduce new participants into discourse as the subject/ergative/agent of a transitive clause. Though they might seem perfectly grammatical, sentences like âA nice man helped me out.â are surprisingly rare in spontaneous speech.
Speakers more often introduce new entities in presentative constructions, in intensive clauses, or as the objects/absolutives/patients of transitives: âA nice man came up and offered to help,â or âI met a nice man there and he helped me out.â
For this reason ergative arguments (or subjects/agents of transitives) are rarely identified in full noun phrases: they are usually represented by pronouns or nothing at all.
(Minthum 1999: 192)
Though not exact, a similar principle applies. In Umu, DEFINITE arguments are more likely to be AGENTS than INDEFINITE arguments.
This left the question: “How do you have an indefinite agent then?”
Reduplication Expanded
Now we will learn more about the behavior of reduplicated verbs.
Reduplication promotes the argument nearest to the verb to AGENT. This means that other arguments are free to perform other roles. Because INDIRECT OBJECTS and INSTRUMENTS accompany a preposition, the ‘other’ argument most likely will fill the roll of PATIENT.
This allows us to shift FOCUS and TOPIC.
Nname’u tiw.
nöna me’u ti’ö
eat shark king
The king eats the shark.
Nnanna me’u tiw.
nöna nöna me’u ti’ö
eat eat shark king
The shark eats the king.
Above, doubling the verb eat makes the closest argument, the shark, the AGENT. The king is left to be the PATIENT. The example describes what happens to the king–the king already being the understood topic of discussion. It answers a question like, “What is happening to the king?.” This works too when the topic is not overt:
“What is happening to the king?”
“The shark eats (him).”
Nnanna me’u.
nöna nöna me’u
eat eat shark king
The shark eats.
Contrast this to the sentence below where the shark is the established topic of discussion.
“I see a shark.”
“What’s the shark doing?”
“He’s eating the king.”
Nnatiw me’u.
nöna ti’ö me’u
eat king shark
The shark eats the king.
Or, when you drop the topic…
Nnatiw.
nöna ti’ö
eat king
(Something)Â eats the king.
“What’s the shark doing?”
“King eating.”
Yes, yes. Very good.
Straddled Verb-Verbs
So now we know this. When a verb has an ARGUMENTÂ on both sides of it, the post-verbal ARGUMENTÂ is the AGENT and the pre-verbal ARGUMENT is the PATIENT. But the agent is also the TOPIC.
This was as good as I was able to get with this issue. But it left a problem. Topics are always definite so that wasn’t the problem. Rather, I needed a way to have a DEFINITE PATIENT with an INDEFINITE AGENT. Reduplication works here too. Easier to see it below.
“What’s the boy eating?”
“He’s eating a shark.”
 Â
Me’unna ‘ara
me’u nöna ‘ara
shark eat boy
The boy eats a shark.
“What is happening to the boy?”
“A shark’s eating him.”
 Â
Me’u nnanna ‘ara
me’u nöna nöna ‘ara
shark eat eat boy
AÂ shark eats the boy
In both cases the boy is the topic and may be dropped. The answer still has the same meaning.
Things got a little hairy and to be honest, this questions been bothering me for years. But as simple as it seems, it took that long to unpack.