Attention
TYPO3 v8 has reached its end-of-life March 31st, 2020 and is not maintained by the community anymore. Looking for a stable version? Use the version switch on the top left.
There is no further ELTS support. It is recommended that you upgrade your project and use a supported version of TYPO3.
Changing Backend Language¶
The TYPO3 CMS backend is available in many languages. These translations are bundled into packages which need to be fetched from the community translation server (https://translation.typo3.org/). Once installed backend users can choose which language to use.
Loading translation packages happens in the ADMIN TOOLS > Languages module.

Click on the "+" icon to activate a new language. A download button appears to the right. Click on it to get the translations. In the docheader is a download icon which will fetch packages for all activated languages. It is recommended to update regularly to benefit from completed or improved translations.
To change the language of the backend, move to the User Settings module, which is accessed by clicking on your user name in the top bar.

Choose "Language" at the bottom, then hit the "Save" button in the docheader. The backend should update itself automatically but you may want to reload the page in the browser. Your backend should now be in Basque.

As you can see, if a translation is incomplete, the backend will fall back to English.
A default language can also be set when creating a new backend user.

Caution
Changing a user's default language will not change the backend language if that user has already logged in at least once, as the language is kept in the user preferences. Such users will need to update their language themselves.