Path: utzoo!utgpu!water!watmath!clyde!att!rutgers!apple!bionet!agate!helios.ee.lbl.gov!nosc!humu!uhccux!lee
From: lee@uhccux.uhcc.hawaii.edu (Greg Lee)
Newsgroups: comp.lang.misc
Subject: Re: Syntactical defininition of English
Message-ID: <2536@uhccux.uhcc.hawaii.edu>
Date: 27 Oct 88 18:44:38 GMT
References: <44600003@hcx2>
Organization: University of Hawaii
Lines: 44

From article <44600003@hcx2>, by dougs@hcx2.SSD.HARRIS.COM:
" ...
" is either too exhaustive to be useful or just simply beyond a CFL.  Hey, if
" a context-free grammer can't recognize the regular expression
" 
"               x  y  z  y  x     (note: this requires a pushdown machine with
" 	     a  b  c  b  a             multiple stacks, more power than an 
" 				       automata equivalent to a CFL can be)
" 
" how the hell is it going to handle English, or Spanish, or whatever?

           x y z x y
Supposing a b c a b  was meant, then the answer is it's going to the
hell handle them if they don't the hell have such constructions.
Whether one does find such constructions in natural language is
debatable -- there is discussion in the linguistic literature going
back about a decade.  At least, it seems clear that they are not
common.

" Remember, we must check proper pluralization, subject-verb agreement, all
" that good stuff.

Since natural languages have grammatical agreement with repect to only
a finite (and rather small) number of categories, and since the
strings that separate agreeing items can be characterized by a finite
number of strings of category symbols, agreement does not pose a problem
in principle.

" For programming languages, the CFL describes the written
" syntax and the semantic actions fill in the context-sensitive features
" we need.

And so it may be for natural languages.

" My wild guess is that our minds use a context-sensitive grammar
" with hundreds of thousands of semantic checks to fill in where the CSG 
" is inadequate for our needs.

The proposal that natural languages are context free is also a guess,
at this point, but I think it's fair to say it's an educated guess.
There is some evidence against the proposal, but in my opinion this
evidence is rather marginal.  Other linguists have other opinions.

		Greg, lee@uhccux.uhcc.hawaii.edu