Performing Language Fallback to English if the context language does not exist.

ItemFallbackController.cs

    public class GeneralController : GlassController
    {
        public ActionResult Content()
        {
            var english = LanguageManager.GetLanguage("en");
            using (new LanguageItemFallback(english))
            {
                var model = GetContextItem<IContent>(inferType:true);
                return View(model);
            } 
        }
    }