#!/usr/bin/perl

use warnings;
use strict;

my %huge_trans = (
	zero  => 0,
	one   => 1,
	ones  => 11,
	two   => 2,
	three => 3,
#	...
	million => 1_000_000,
	);

my $rx_word = qr/\b\w+\b/i;

print <> =~ s!($rx_word)! $huge_trans{lc $1} // $1 !ger;