Omaha fricative set

[Rankin, Robert L]

These are interesting observations.  It's not unexpected that people whose use of a native language is fairly fluent but who are, nonetheless, English-dominant, might begin hearing "sounds" rather than phonemes in the native language.  This is fairly common, especially if a particular sound is allophonic in the native language but phonemic in English.  It would take some experimentation as well as introspection to determine the status of "muted S" in Omaha.  You might tape a speaker saying 'foot' and 'seed' a number of times (keeping track yourself of which is which) and then play them back to someone who wasn't in on the discussion and ask him/her to identify the words.  If these are really distinct phonemes, they shoud get the words right 100 times out of 100.  You could throw 'yellow' in a few times just to muddy the waters a bit.
 
I do tend to believe that "muted S" is something other than a previously undiscovered Omaha phoneme.  That said, however, it is still the case that we have some instances in which the Comparative Dictionary shows "irregular" sibilant sets, and the 'chicken' word you mention is one of them ('seed' and 'foot' are not).  Normally Omaha /s/ matches Dakotan /s/ and /z/ matches /z/.  
 
The exceptional cognate sets that I have found are:
 
OM  sikka  'chicken'    (but ziziga 'turkey')
LA   ziNtka  'bird'         (but zic^a 'partridge')
 
OM  sattaN  'five'
LA   zaptaN  'five'
 
OM  siNga  'squirrel'
LA   zic^a  'squirrel'
 
It is barely possible that we have missed something in the fricative sets.  The above words ought to be checked in Omaha to see if they contain the "muted S" rather than the normal one.  Wouldn't it be interesting if that were the case?  Think of the mess it would make of "fricative ablaut".
 
Dorsey heard the "muted" sounds, generally preceding a sonorant, and tended to call them "mediae".  It's the ones preceding vowels that are interesting here.
 
If you're interested in the sets of European sibilants that John was mentioning, the article to start with is probably "The Mediaeval Sibilants", reprinted in _Readings in Linguistics_ ed. by Martin Joos.  The author talks about the ones in Romance and Germanic at length.  
 
Bob

> In the past, we've roughly assumed a set of three oral fricative locations,
> each of which may be voiced or unvoiced:

>   s     s^     x^
>   z     z^     g^

> Second, the "muted" versions of s and s^ seem to be more widespread than we
> had supposed.  According to one of our speakers, we seem to have a minimal
> triplet of words in the s series:

>   si        'foot'   (<MVS *si)
>   s.i       'seed'   (<MVS *su)
>   zi        'yellow' (<MVS *zi)