Here are the steps to create an employee (team) and change the admin language from the back-office in Magento:
To create an employee (team) in Magento, log in to the Magento admin panel and navigate to ‘System’ -> ‘Permissions’ -> ‘Users’.
Click on the ‘Add New User’ button to create a new employee (team) account.
Fill in the required information, such as the user name, email, and password.
Assign the appropriate roles to the user by selecting them from the ‘User Role’ drop-down menu.
Click ‘Save User’ to create the new employee (team) account.
To change the admin language from the back-office, log in to the Magento admin panel and navigate to ‘System’ -> ‘Configuration’.
Under ‘General’ -> ‘Locale options’, select the desired language from the ‘Locale’ drop-down menu.
Click ‘Save Config’ to save the changes.
Now, the admin language is changed in the backend.
Note: The above steps are for Magento 2, but it may vary depending on the version of Magento you are using.