#!/usr/bin/perl
$vowels='aeiouy';
$cons='bcdfghjklmnpqrstvwxzy';
%map={C=>$cons, V=>$vowels;
for $class=($vowels, $cons) {
  for (split //, $class) {
    map{$_}.=$class;
  }
}

for $char (split //, shift) {
  $pat.="[$map{$char}]";
}

$re=qr/^${pat}$/i;
print "REGEX is $re\n";
@ARGV='/usr/dict/words'
  if -t && !@ARGV;
while (<>) {
  print if /$re/;
}