I inherited maintenance of a Drupal 7 site and I don't have much experience with drupal but there is a content type called 'Materials' that we would like to be able to view it's listing representation in different languages. So /materials lists everything in English, but /es/materials should list everything in Spanish but it has both Spanish and English entries. How can I eliminate the English entries so only Spanish ones will show. And, why are English entries displaying in the first place?
Also, to make view results correspond to the language switcher, add a filter for Content Translation: User's Current Language, which is the language that an authenticated user has set in the user settings (it is NOT the same as the current browser language or the site language).
If no option for the User's Current Language is available in the filter criteria form, then verify your configuration at Configuration -> Languages -> detection and selection: The order should be URL, Default, User and not something like Default, URL, User (as mentioned also in https://www.drupal.org/node/1701854#comment-6279474).
Note: The Internationalizations Views module only has an alfa version for D7, but right now there are over 41K users using this version. Therefor I think "DEV" is not a valid release qualifier for that version anymore, because +41K users can't be wrong, right?