I'd just write a frontend for grep, and let it do the hard work:

$ARGV[0]=~s{([2-9])}
           {'['.substr("abcdefghijklmnoprstuvwxy",3*($1-2),3).']'}eg;
exec 'grep', "^$ARGV[0]\$", '/usr/share/dict/words';
[download]

That's what I call 'multilingualism' ;-)