How to get current route information in OnActionExecuting

My URLs look like:

www.exam开发者_JAVA百科ple.com/{languagecode}/{controller}/{action}/{id}

where language code is en-us, etc.

From the OnActionExecuting event, how can I get these values?

protected override void OnActionExecuting(System.Web.Mvc.ActionExecutingContext filterContext)
{
    var languagecode = filterContext.RouteData.Values["languagecode"];

    base.OnActionExecuting(filterContext);
}