Re: THEORY: Any rules broken?

Trebor Jung wrote: 
  >In my conlang Tsaan, I've decided that there's no 3p. I was wondering

 1. if it's OK to replace the assumed 3p pronominal prefix (in this case) with
the external argument represented by it in, say, English:

  sôô+kal+taal
  child+fish+eat
  'The child eats the fish'>

  Many languages get along without any overt verbal affix for 3rd person, as David P. pointed out. 
  Others may require marking for pron.subjects but not for nouns-- your example, perhaps.
 And others may require marking for subjects, but allow it to be deleted in
certain cases, e.g. emphasis. Kash does:
  manahan numu /1s-eat  fish/  'I ate the fish' ordinary statement.
 MAM nahan numu /Pronoun-1s/emph. eat fish/ '_I_ [not someone else] ate the
fish' (heavy stress on _mam_)

 >2. if it's OK to use 4p for both the meanings "someone unknown" and "someone
already mentioned and identified in the conversation".>

  Isn't that self-contradictory? 

  IIRC 4th person most often refers to a second 3rd person referent other than one just mentioned. 

  "John told Bill that Henry was sick" -->
  "John told him(3d) that he(4th) was sick"
 Of course this can also go to "He told him that he was sick" where each
pronoun refers to a different person; with context it's perfectly clear and I
doubt if many (any?) natlangs bother with that much distinction.