If you have more than one language installed and enabled in your X-Cart store, you can switch your store's Admin language using the language selector in the header:
If you do not see the language selector in your store Admin area's header, you probably do not have any languages other than the default one enabled in your store.
Go to the "Languages" page of your store Admin area (Store setup -> Translations) and check if any languages except for the default one are enabled:
Install the related language pack as described in Installing Language Packages if the necessary translation is missing.
Related pages: