I need to create multilingual static block. So far I have
created static block with id ‘delivery_returns’.

$deliveryBlock = Mage::getModel('cms/block')
                     ->setStoreId(Mage::app()->getStore()->getId())
                     ->load('delivery_returns');

echo $deliveryBlock->getTitle();

/**
 * You shouldn't print the content directly (although I'm assuming it's for debugging purposes only).
 * Use the code below, so as the possible content directives (the "{{ }}" thingies) would be interpreted.
 * Check out Mage_Cms_Block_Block::_toHtml().
 */
echo Mage::helper('cms')->getBlockTemplateProcessor()
                        ->filter($deliveryBlock->getContent());