Reverts changes to default language configuration that reduced functionality for some bilingual users.

When a language is not specified, the language interpretation is left up to Google to decide how the search results should be delivered. If any user is affected by IP geolocation, where the server that their instance is deployed on (or VPN that they are using) causes the interface or search results to be delivered in a different language than desired, the correct solution should be to set the interface/search language to a non-default setting.