Magento – Set different catalog price rules/promotions for each language on a multi-language store

This is possible. Given that you already setup your stores, http://www.magentocommerce.com/knowledge-base/entry/overview-how-multiple-websites-stores-work.

Just change the setting in:

   Admin > System > Configuration > Web > 

Here you need to change the Current Configuration Scope to your Specific Website > (Change the Base URL)

If you wanted this as a feature you can write a module, and observe the save product event and loop through all the stores and either:

• condition based looking for "english" if they are named like that
• hardcode the id's
• provide a configuration option in the admin to select the english stores.
• add an attribute to the store object

Another way to do it as a one off:

<?php

require '../app/Mage.php';

$englishStore = 1; // English Store (the one you want to copy from)
$attribute = "short_description"; // Attribute to copy

foreach (Mage::app()->getWebsites() as $website) {
    foreach ($website->getGroups() as $group) {
        $stores = $group->getStores();
        foreach ($stores as $store) {
            //store object
            //print_r($store->getData());

            // if english found in name or change this so it's hardcoded store id's
            if (strstr($store->getData('name'),"english")) {

                $StoreToUpdateCollection = Mage::getModel('catalog/product')->getCollection()
                    ->addAttributeToSelect('*')
                    ->addAttributeToFilter('store_id', $store->getData('store_id'));

                foreach ($StoreToUpdateCollection as $product) {

                    // get the description from the base English store
                    $englishProduct = Mage::getModel('catalog/product')->setStoreId($englishStore)->loadByAttribute('sku', $product->getData('sku'));
                    $newValue = $englishProduct->getData($attribute);

                    // update the attributes for the current store for the product ID
                    Mage::getSingleton('catalog/product_action')->updateAttributes(
                        array($product->getData('id')),
                        array($attribute => $newValue),
                        $store->getData('store_id')
                    );
                }


            }


        }
    }
}

I have not tested the updating part, would suggest trying this on a dev version.