The selected interface language setting in Drupal

A client of mine asked about locking the interface language on their multi-language site to English. By default, Drupal displays the UI based on the language version. Which sometimes means that if the site has several language versions, some users were forced to navigate the UI on languages they didn't know. This would make content updates a lot more difficult than what it needed to be. I know from experience that navigating the Drupal UI in a language you don't know a word in, is extremely difficult.

Instead of completely locking the UI to English, I decided to allow the users to select what language they wish to view the UI in. This way people with limited English skills could still view the UI in their native language (if their native language is one of the language versions). The setting has defaulted to English so if the users didn't feel the need to change the UI from English to another language; they didn't have to do anything.

We agreed that the content types and instructions were only created in English, which meant the users still would see some English no matter what language they selected from their user settings. In this case, everyone knows English, so they didn't desire to have the content types to be translated into other languages.

A few issues with the selected interface language setting

The functionality doesn't work properly if your site's default language isn't the same as the language without a prefix in the URL. The pages on the non-prefix language version would only give 404 errors. If the default language is the same as the language without the prefix, everything works as intended. Also, if all language versions have prefixes, the functionalities work properly no matter what your default language is.

If you have content that is translated via Drupal's t-function, the text will be displayed in the language the user has selected. This can confuse logged-in users so make sure you inform your users if you use this setting!

Drupal's default language selection drop-down block works by selecting the interface language. If the selected language interface is selected, the drop-down displays the language you have selected and doesn't work properly. What you can do is instruct your users to change the language version from the address bar or just don't use the default language selector block at all.