Graphene Change Language to Spanish

I updated the wp-config.php file with define(‘WPLANG’, ‘es_ES’); but i am not seeing any change, is there another step? If not my next question would be: I am showing home page panes, and the home page lists the two most recent blog posts. The blog posts end with a button that says in english ‘read more’ but the site is spanish, where would i change that? TIA