How to set language for sales items in order conf mail?

So {{layout handle=”sales_email_order_items” order_id=$order_id area=”frontend”}} renders a table with all ordered products by the customer in the Order confirmaiton E-mail. This table is always in English. How do I change the table headers like “Items”, “Qty” and “Price” to another language? Do I need to declare the language somewhere? Thx in advance