Pig Latin words are not supposed to begin with consonants. flea becomes ea-flay and leaf becomes eaf-lay. If you use hyphens, you can create that distinction. If you don't want to use a visible character, though, insert a NUL. Oh, and since when does about become aboutway? I never heard of the 'insert a w' rule.

s/\b(qu|[^\W0-9_aeiou]+)?(\w+)/$1?"$2\0$1ay":"$2\0ay"/egi;
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The preceeding code allows you to decode the string. While it does effect length(), a simple (?) work-around would be:

package PigLatin;

use overload (
  q{""} => sub {
    (my $str = ${ $_[0] }) =~ tr/\0//d;
    return $str;
  },
  fallback => 1,
);

sub to {
  my ($class,$word) = @_;
  $word =~ s/\b(qu|[^\W0-9_aeiou]+)?(\w+)/$1?"$2\0$1ay":"$2\0ay"/egi;
  bless \$word, $class;
}


sub from {
  my $word = substr ${ $_[-1] }, 0, -2;
  # $word has the \0 in it
  return join "", reverse split /\0/, $word;
}

1;
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This module would be used as so:

use PigLatin;
$plain = "Practical Extraction and Report Language";
$funny = to PigLatin $plain;
$reg   = from PigLatin $funny;
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length($funny) would be 50, but length($$funny) is 55, due to the 5 added NULs.

$_="goto+F.print+chop;\n=yhpaj";F1:eval