The basic idea below is using "match global". There will be problems with contractions, like this isn't perfect.. have fun..hope it helps..

#!/usr/bin/perl -w
use strict;

my $text ="";
while (<DATA>)
{
  s/\n/ /;          #not graceful way of \n
  $text = $text.$_; #not either, but not main point...
}

#main point is to use match global (/g)
#think about /m and /s options also
#this is just an example of an idea....
#
my @quotes = $text =~ m/["'](.*?)["']/g;
print join("\n",@quotes),"\n";
    
__DATA__
"Mary and a little lamb", she said.
She thought 'Hang on a tick'. this 'is
a line spanning quote' and course
not! I really do not know about the
really stange things, "But this is another
line span quote"
Nobody loves me
"Mary and a large lamb"
this is just nonsense
the PM said 'something'

__END__
OUTPUT:
Mary and a little lamb
Hang on a tick
is a line spanning quote
But this is another line span quote
Mary and a large lamb
something
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