Hello!
$filter = new Zend_Filter_LocalizedToNormalized(array('locale' => 'es_CO'));
$val = $filter->filter( '1' );
$val should be 1000000 now, but is an array with date informations:
array ( [date_format] => "d/MM/y", [locale] => "es_CO", [day] => 1, [month] => false, [year] => false)
I found similar issue with other localization which have been already fixed.
The same problem exists with locale="es_CL", "es_CR"