Currently, language change of the user agreement (using the link above the agreement) have no impact to the language used for remaining interface elements. The enhancement request has been created to allow language link (in the top right corner) to change the language of all user interface elements including the text of the User Agreement.
An enhancement request (VSTS105452) has been created detailing the feature above.
The product team will evaluate the request and this feature may become available on a future release of the product.
Please refer to this article for updates or contact support referencing the Enhancement Request ID: VSTS105452.