see http://share.ez.no/forums/ez-publish-5-platform/translation-loading-accross-siteaccesses for initial description.

Resolution was discussed with Jérôme Vieilledent : update view manager to limit languages in https://github.com/ezsystems/ezpublish-kernel/blob/master/eZ/Publish/Core/MVC/Symfony/View/Manager.php#L259

PR is on its way