Restrict language content for a given role
A way to achieve it can be this.  Note I am assuming you are using the standard node-based translations, and not entity-based translations.

Suppose the content is a node-type one and the content-type is called Page_en_es.  Give permissions at /admin/people/permissions:


View own unpublished content, Page_en_es: Edit any content etc to translator users
View published content to anonymous users.


Then, whenever a translator edits or creates the Spanish content, s/he will set it (=node) to be not published.  And the Spanish version won't be seen by anonymous users.