my $word = q{-\w'(),};

s{
  (^|[^$word])
  (
   (?:([$word])\3)+
  )
  (?=[^$word]|$)
 }{
  my @x = ($1, $2);
  $x[1] =~ s/(.)./$1/g;
  join '', @x;
 }xige;
}