When describing the language concept in Optimizely, the following language setting types are mentioned:
**System language**. Controls date/time formatting, sort order, and so on.
**User interface language**. Controls the localized (translated) resources to display; determines the user interface language.
**Content language**. The preferred language when displaying content. Content can be a page, a block, or a product catalog item.
Conceptually, globalization in Customized Commerce works the same way as in Optimizely Content Management System (CMS). To learn about language management in Optimizely, see [Globalization](🔗).
Not all globalization features described for the Optimizely platform and CMS apply to Customized Commerce. Some features work differently, such as in the legacy parts of Commerce Manager.
By default, the Customized Commerce user interface is available in a number of languages, and you can localize it further with additional languages. The localization procedure differs somewhat between the Commerce user interface and the legacy Commerce Manager backend system.
## Commerce user interface
You localize the pluggable add-on user interface using the Optimizely localization services in the same way that the CMS does. See also [Localization service](🔗).
### Commerce Manager user interface
To add languages for localization of the user interface in the Commerce Manager backend system:
Change the associated key values of your resx files under App_GlobalResources. Each key/value pair corresponds to a particular function in the Episerver Commerce administration interface.
To keep existing resx files while supporting additional languages, copy and rename the existing resx files. Open each resx file using Visual Studio, and edit each key/value pair to match your language.
### Order data
This feature applies to Commerce version 13.21 and higher.
By default, the localization of order data is enabled. If you do not use order data localization, you can disable it. Disabled order data localization saves storage and improves performance by reducing read/write operations.
To disable order data localization, go to appSettings in the _web.config_ file and set **episerver:setoption:Mediachase.Commerce.Orders.OrderOptions.DisableOrderDataLocalization**, **Mediachase.Commerce** to **true**.