There are different ways how to use Phoca Cart in multi language mode.
Internal Strings
Basic component, module and plugin strings are standard Joomla! language strings which can be translated by Joomla! INI files (for example: de-DE.com_phocacart.ini).
Content Strings
If you need to translate content strings (products, categories, ...) there are different ways how to achieve it:
(1) Using default Joomla! feature - this means that each language will be applied for each item. For example products: One product becomes two or more for each language. So Product 1 will be stored as two products - one for English language, second for e.g. German language. The same way like Joomla! articles are stored.
(2) Using Falang extension. See Falang files for Phoca Cart
(3) Using Multilanguage CK extension. You can find modified version of this extension on Phoca Cart download website. This modified version adds extra features for Phoca Cart component.
Example of Multilanguage CK plugin syntax:
Billing - Multilanguage CK plugin syntax