k?u and related argument problems.

[R. Rankin]

Excuse a question from someone who has always done more
phonology and morphology than syntax.  Pam wrote
something in one of postings to the effect that "you
can't just add nouns in Dakotan sentences."  (The quote
is inexact because I don't have the message here on my
home computer -- sorry.)  This was in reference to the
argument structure of k?u.

I guess I'm having a little trouble picturing what this
means and what its implications are.  Could Pam or
anyone give me an example of this restriction,
especially compared to some language (English would be
fine) in which you *can* add such forbidden nouns,
whatever they might be (but wouldn't be able to in
Dakotan)?

Sorry to be so thick, but I'm missing something here.
(And I'm also thinking about how this whole discussion
might play out if you accept the 'pronominal argument
hypothesis' for Siouan.  Then all the nominals would be
something like adjuncts, and I'm curious to know what
the restrictions on such adjuncts might be.)

Bob