assuming that English and Spanish use $_SESSION['languageID'] == 1 and $_SESSION['languageID'] == 2, then you could use the following code to change the number format that the cart will use:
<?php
if(isset($_SESSION['languageID']) && ($_SESSION['languageID'] == "1" || $_SESSION['languageID'] == "2")) {
$yourCartName->NumberDisplay = 0;
} else {
$yourCartName->NumberDisplay = 1;
}
?>
this code should come just after the GetContent line on the cart page.