How is the way to specify action/controller for a Razor Html.BeginForm???

It seems to me that it's Html.BeginForm(action, controller...), but in name of controller, we've to use the friendly url, not the controller name (error 404 not found).

But what happens with language????, is it necessary to to write the code like this???:  Html.BeginForm(action, language/url...)... for example, to access the index action of productpagecontroller,

we have to write something like Html.BeginForm("", actual-language/products...), is that right??? Can anybody explain me how to work with Html.BeginForm for multisite multilanguage websites????

Thank you in advance.